You need a google account, but not a google workspace account, to sign up for a waiting list to get access. That's pretty far from "Google makes its text-to-music AI public".
You need to log in to use ChatGPT too—you can't open an Incognito tab and use ChatGPT. By that definition, ChatGPT is not available to the public.
Needing to be approved from a waitlist is the difference.
Well you can use it in Incognito... if you login
Well, search , for example. No account needed. The DNS maybe as well.