I made an error in my initial attempt to break it down, so deleted.

The goal is definitely to have it work both ways (at least it was in 2021, tbh I don’t follow Monero development closely) but it will take a hard fork of Monero for it to work.

Here is a link to a post by Comit breaking it down, but basically in its current form you cannot “buy” Bitcoin with XMR. You must “offer” then “sell” your XMR for Bitcoin. The actual on-chain swap must be initiated by the Bitcoin/buy side.