In the future not everyone will have the right to use layer 1, ARK for example offers privacy by default and without custody, also because of its architecture you can have hardware wallets in the absence of solving the problem of the rounds with the notes. With bitcoin L1 you can use coinjoins and get the same or more privacy than with Monero. On the other hand Monero is not scalable and its dynamic block size equates to losing decentralization if it were to be massively adopted.