That argument doesn't hold water. It's best practice for offline first PWAs to not require sign up when you get started. Unless there is ever a feature to sync across devices or cross users, there is no reason to EVER sign up, and even then, you can make signing up something they do AFTER they decide to keep using your app and realize they do in fact want syncing.

Signup was added so users can manage multiple accounts on the same device, like separating personal, family, or business cash flows, but I understand it adds friction for first-time use so I am considering a guest mode to let people try it out instantly.