I guess the difference is that on-chain you still just had one transaction. Nobody knows if it’s you who received it or somebody else, but neither does anyone know that when I just do a normal transaction. But there is only one possible history. With a coinjoin the link to the history of the UTXO is broken, because a hand full of people does a transaction together, with the same amount, and therefore it’s hard (at some point impossible) to say, what the history of your UTXO is.

As long as you stay off-chain Cashu seems good, but on-chain it doesn’t really change anything imo