RealID seems to have added some verification requirements on US passports, but it doesn't look like it made US passports a form of "RealID".
It proves my identity as a US Citizen as much as it has to be.
Unlike most driver’s licenses, a passport card doesn’t expose one’s address. This makes it a great form of ID to use in non‐airport situations as well.
Coincidentally, this is also how it works with German passports. You're legally required to have either an ID card or a passport (or can have both.) The former has your address and comes with a bunch of ever-changing digital signature/ID features (that you need a special reader or app for). The latter is just a biometric (still RFID but well) passport, with only the city (issuing authority) listed.