Comment by JanisErdmanis

A significant obstacle to adoption is that cryptographic research aims for a perfect system that overshadows simpler, less private approaches. For instance, it does not seem that one should really need unlinkability across sessions. If that's the case, a simple range proof for a commitment encoding the birth year is sufficient to prove eligibility for age, where the commitment is static and signed by a trusted third party to actually encode the correct year.