There's no reason why you can't Coinjoin/Lightning your UTXO's in conjunction with Monero - it's a good privacy tool and supplement to Bitcoin IMO.
If you are already using coinjoin and Lightning, then what supplementation does Monero provide?
Coinjoin is only forward facing privacy & lightning has a lot of privacy holes. Monero as the final spend is a good idea IMO. Or swap Monero to Lightning. Mix it up though, you don't want the same patterns.