Especially if you don't have a phone and don't want to use your google account for anything but gmail, for privacy reasons. Both of these point apply to me, for instance.

Also, the dark pattern where it shows the interface and lets you enter a prompt/set settings, but then pops up the 'create account' dialog when you press submit is pretty annoying.

same, precisely the reason I haven't signed up yet. GLM can be used without any account fwiw

openrouter's a good option, though it has a price markup