Well, spend and replace is only superficial if there is no reason to spend in the first place. The 'replace' part is only relevant to a person who has income in non-Bitcoin and also has some reason they prefer to spend in Bitcoin.

For myself, I find several reasons to prefer spending in Bitcoin where possible - mostly related to security and not revealing personal information, but increasingly, the broken nature of the traditional finance system plays in too.

I think the right critique of spend and replace is simply that the friction and costs of buying Bitcoin can be a real pain, so minimizing the number of times you do it is desirable. Debatable point though.