Why would an Airbnb host ask me to cancel my request to book their Airbnb, instead of declining that request themselves?

It’s simple. A Host cannot decline too many requests even if IB is turned off. After 5 declined requests Airbnb sends you a warning. Your listing is deactivated if you refuse too many bookings. "Request to book" can be annoying if you’re a guest. You wait a maximum of 24 hours to get a yes or no answer, and that might have a negative impact on the platform credibility. Airbnb prefers IB by default. If the guest withdraws the request the host is not affected.

I had a host ask me to cancel because he didn’t realize it was for 1 night and he doesn’t like to accept 1 night reservations. I told him that he shouldn’t have accepted it, then. I called airbnb and they told me the hosts get charged $50 for every cancelation on their end. I asked what if I don’t cancel on my end? And they said that the booking stands. I asked well, what if they don’t let me enter the premises on the date of the booking? They said the host would be dropped from Airbnb, then. But I didn’t trust the host to not leave me stranded so I canceled, anyway. I stick to strictly hotels now.

The host could have resolved this much easier by just blocking one day of your reservation attempt (I’m taking it is a reservation attempt as by your comment here: it doesn’t show up as reserved in my account. I only made a booking request: i.stack.imgur.com/yLKB0.png)

The platform would then show the reservation as "Not Possible"

To answer your question, why would the host not decline himself?

• not aware of above
• fearing to lose the Superhost Status: "To meet this criteria, cancel fewer than 1% of your
  reservations of the last 4 trimesters"
• fearing to fail Basic Requirements: "Accepted Reservations Target 88%"
• avoiding the penalty for cancellation, which is currently 10% of the booking value

More insights (you need to login to reach that page)

There’s nothing too unusual here. Apparently the host has instant booking off, or you made a booking request for some other reason¹. The host says that actually the dates are unavailable because another guest has extended his stay. If true, the host should have blocked the calendar, but it might not be true and he simply doesn’t want to host you. Either way, he’s replied "no, it’s not available".

As to why the host asked you to cancel, it is likely because the host doesn’t want to affect his acceptance rate. Hosts are affected if they do not accept enough requests to book. Host’s acceptance rate is a metric important for maintaining superhost status. If you cancel, that doesn’t affect the acceptance rate.² This just might be his habit to curb that problem. On your part, a request has you committed for 24 hours. He could still accept your request and you’d be charged for the stay, then you’d have to depend on the cancellation policy to get your money back. An inquiry leaves you with no commitment.

Just move on and book somewhere else. If you’re feeling generous, cancel the request.

1. Some guests will make requests just to ask for a discount, or to break house rules, like bringing a pet or hosting a party. If this is why you requested, as a host, I’d suggest you take this as a polite "no thank you". I’d further suggest you please stop doing this. It’s a little bit rude.

2. When a host receives a reservation request, he is supposed to accept or decline in the first 24 hours. The acceptance rate is tracked and needs to be above a certain metric. Doing nothing defaults the decline option, and counts against the host’s response rate and acceptance rate. Inquiries on the other hand offer the host "pre-approve" and "decline". Neither option is added to any metric, but the response metric still applies. You must have put in a request, not an inquiry, because I don’t think you can cancel an inquiry (that wouldn’t make sense), and the host can decline an inquiry without penalty.

_{Footnote: Since I got some static in the comments about the Airbnb policies regarding requests, inquiries, and the host’s metrics and when they are affects, here are the relevant support articles from Airbnb.}

<sub>1. Decline a trip request
2. Respond to an inquiry
3. What are response rate and response time and how are they calculated?
4. Booking inquiries
5. Understanding response rate and acceptance rate Quotes: "A booking request means that the guest is officially asking to book your listing and is waiting for you to accept or decline. As far as your acceptance rate goes, we only measure the final outcome of the booking request, and there are just three possible actions you can take: accept, decline, or let the request time out. If you let a request time out—even if you answer questions but take no action to approve or decline a request within 24 hours—that’s considered a decline." | "if you decline an inquiry, your acceptance rate is not affected" | "low response rates can impact your eligibility for the Superhost program, and acceptance rates can impact eligibility to become a Plus host. And hosts who have very low rates could face penalties, including having their listings paused."</sub>

Yes, if a guest makes a reservation request or a reservation, there are potential penalties for an Airbnb host declining or cancelling it:

[W]hen Hosts cancel on guests for preventable reasons—like
accidentally double-booking or wanting to host friends and family
instead—guests lose the confidence to book on Airbnb, and this impacts
all Hosts and hurts our entire community… if a Host cancels a
reservation for a preventable reason, an updated fee will be deducted
from future payouts. The fee depends on the reservation amount and how
close to check-in the reservation is canceled.

In this situation, the host probably just forgot to update their calendar on Airbnb after an existing guest extended their stay via another website. The host likely was concerned about how their performance metrics and hosting status could be impacted by declining this double booking.

Double bookings are not uncommon; sometimes they can happen very quickly during peak travel times.

Airbnb can be less than transparent about details sometimes. However, Airbnb makes it clear that:

A Host must promptly cancel a reservation that the Host cannot honor
and may not encourage the guest to cancel the reservation.

Accordingly, the host should decline or cancel the booking as quickly as possible to minimize inconvenience to the guest and do their best to promptly update their calendar in the future.