Oh, sorry, my answer totally did not address your question, I didn't see the top level question.
No, coinjoin has nothing to do with cashu.
This is a LN address server, which when it gets called fetches an invoice from a cashu mint, as soon as it gets paid, the mint issues new ecash tokens (nuts), sends them to the LN address server, who then forwards them to the npub that was in the address.
We've been fighting with these phishing sites for years, they keep coming back...
It's news to me that they clone even other bitcoin wallets that are installed on the machine, that's crazy.
Stay safe out there plebs, and always verify signatures!
Also, wasabi comes with an internal update mechanism that checks signatures as well, and there is no risk of visiting a wrong website.
Every coinjoin is trivially identifiable.
There are steganographic privacy techniques, like coinjoinXT and coin swaps, but they are very complicated, expensive, and so far not implemented.
Nevertheless, coinjoin is useful, as it hides common input and output ownership.