I'm not sure what it actually means. For instance Apple Pay is probably not supposed to replace your actual credit card, but if you can live your life without ever using the physical one, that's just legalese.

If it really doesn't do much (i.e. only help to pass TSA lines), then perhaps it should be called something else. If it effectively can act as a passport in 80%+ more situations, "not a replacement for xxxx" will just be legalese for most users.

Not useful for much in the real world, but extremely useful for online age verification.