The EU already has some form of digital ID in fact, every government provides some kind of OIDC-like service tied to either smart cards or accounts that authenticate the user against a government. The digital wallet solution is an extension to that system that will allow foreign EU citizens to authenticate themselves more easily (eIDAS 2 already implemented an OIDC-like solution but implementation isn't automatic) as well as offer to store the (often mandatory to carry) ID on your phone.
The "what if you buy alcohol for your kids" sscenario of somone giving someone else their age verification tokens is tired and nonsensical. You can already do that in the real world. We accept that risk and, depending on the country, make it a crime in case they do catch you. It hasn't made liquor stores send someone along to see you drink your booze or watch you enjoy your porn mag.