Their dev portal is constantly broken in different ways, it blocks you from making changes at random because it needs to run some kind of heuristics to see if you’re doing something malicious (even with webauthn 2fa).
We recently tried to get a Facebook app approved to use the pages_messaging permission. You need to have test users to pass verification. Unfortunately, you can no longer create test users on their platform since October of this year. If you try to use a real dummy user, it will get banned immediately when the application testers log in from another country.
Aside from that, you end up with corporate assets being owned by people’s personal Facebook accounts, because there’s no reasonable way to use SSO or similar. It’s just downright terrible.
I’ve used the offerings from all of the big tech companies, and Facebook/Metas is far and away the most hostile. You get what you pay for.
I will eat my hat if Meta successfully builds a cloud services platform for other tech companies given the state of their developer tooling in all their other business lines.