Not sure whats the play here, there is no world where this can turn out good. Cloudflare is more or less infrastructure provider, this idea of some user delegating permissions to their account to some third party client for infrastructure is ripe for abuses. If companies like AWS are not doing it then its for a good reason.
Do you understand what OAuth is? It’s like an API key but less likely to be abused. This is a good thing. It helps security in many ways and makes security flows more safe than carrying around a token.
How different is this to, eg, the Google developer program, in which I can create a new OAuth client for Google users?