Agreed, it should be substituting cash IMHO. Bitcoin is more of a global banking system replacement. When you need spending money, swap to monero and buy groceries etc...

If you need a large official international transfer, like buying a house or a business transfer, Bitcoin is perfect for the task.

If you need a large transfer and privacy is of outmost importance, you still can do that with Monero.

Monero is not suitable as a store of value, it is suitable for almost everything the rest.