You can get a real id without being a citizen so it shouldn't be used as proof of citizenship.

From the California DMV site:

> Any Californian who can prove their current legal presence in the United States (U.S.) with one of the accepted identity documents (original or certified copy) is eligible to receive a REAL ID driver license or identification (DL/ID) card. This includes all U.S. citizens, permanent residents who are not U.S. citizens (Green Card holders), and those with temporary legal status, such as recipients of Deferred Action for Childhood Arrivals (DACA) or Temporary Protected Status (TPS) and holders of a valid student or employment visa.

https://www.dmv.ca.gov/portal/driver-licenses-identification...

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.

I generally do this anyway; about the only time I carry a passport while just out and about in another country (note: not risky ones) is if making large purchases that will be VAT-refundable. Do merchants accept the card in lieu of passport for verifying you for VAT exemption? Many will take a photo on the phone, but not all.