I don't think anyone is brave enough to create that kind of cross-chain bridge involving XMR (at least not someone looking to keep the business long-term and profit from it). There is already an ongoing pressure to delist privacy coins on CEX, any platform aiding anonymity and privacy will be attacked as well.
If privacy has a value, people will try it, especially if it is built on blinded bearer certificates
[1] or there is no central point of failure, then everyone will try to use it.
There is already a similar solution called Tornado Cash
[2], but it is a decentralized mixer based on smart contracts, so it runs on Ethereum Virtual Machine-compatible networks more than Bitcoin or Monero.
Mixero (Bitcoin Mixer)
[3] claims to have a mixing method based on the Monero bridge, but the mixer is centralized and we cannot verify the validity of these claims.
I think there are disadvantages to this to more than the advantages. They are too centralized as they claim to be decentralized platforms. For instance, the wormhole bridge that was hacked about a year ago, to date the hack tokens has not been recovered and the tokens are been move from one Dexes to anotherm.
I agree with you, all of these bridges are centralized, but things can be improved by making them decentralized so that the service can be hosted (something like BISQ) and a multi-signature address can be used.
It is easy to swap monero to bitcoin and vice versa using atomic swaps, bisq and other small exchanges.
This is true, but we cannot consider it a Bitcoin mixing. For example, if my Bitcoin address is added to OFAC blacklist, then using bisq will move this problem to another user, but it will not mix bitcoins. The government can easily place warnings that you need to obtain Proof Of Source before desposting to any CEXs.
[1]
https://en.bitcoin.it/wiki/Blinded_bearer_certificates[2]
https://en.wikipedia.org/wiki/Tornado_Cash[3]
https://mixero.io/