Basically this means you as a user dont have to do anything but switch away from projects that depend on SystemD's UserDB (like Gnome), not SystemD as a whole

You can also just... not put your PII into UserDB. It can store clear names, mail addresses, postal addresses and now birthdates... but it can also just serve as an interface to /etc/passwd. Which conveniently also works with LDAP accounts (unlike your hand written /etc/passwd parser) if you're an organisation that uses LDAP.

This is the entirety of what UserDB knows about me:

userdbctl user --output=json $(whoami)
{
        "userName" : "sky",
        "uid" : 1000,
        "gid" : 100,
        "homeDirectory" : "/users/sky/home"
        "shell" : "/run/current-system/sw/bin/fish"
}

I don't expect that to change with this PR.