So, if someone uses Bisq, can they change their coins and at the same time kind of "wash them out" and make them "clear"? Sorry for my question, but I don't know much about Bisq (besides the basics), although I'm very interested in joining and starting to do more trades there.
No, Bisq
is a software that:
1) facilitates users to transact and exchange assets & currencies
2) is peer-to-peer
3) is decentralised, meaning that there's no central authority acting as middleware in the transactions
Bisq
isn't a software that launders money.
It's not a tool to distort the history of the coins you own, rendering them untreacable.
You can use Bisq to convert your Bitcoin to other currencies (both crypto currencies and fiat currencies).
For example:
(a) you can sell BTC for GBP and receive the GBP on revolut.
(b) you can buy BTC spending EUR in the form of an amazon giftcard.
(c) you can exchange BTC for ETH and vice-versa.
Like Trevoid said, if you want to, basically confuse, chain analysis companies and make them lose you traces you can indeed convert BTC to XMR.
If you do so, only you and the person who sells you the XMR knows about this transaction.
Owning XMR and spending in XMR can be good for privacy because Monero is a private coin, meaning it can't be definitively traced back.
If you want to keep BTC, you can convert to XMR and then back to BTC, but in this case you will receive a UTXO that you have no idea where it comes from. Which is exactly what happens with your initial BTC that you had. So it doesn't help, unless you know for a fact that you must for some reason get rid of the BTC you have and get random BTC in return.