Consider that a ‘username+password’ is much harder to ‘revoke’ individually. As in, you can have 3-4 API keys in use, and can revoke any one of them without having to change a password.
You can also change password independently of the keys, or have it linked so keys are revoked on a password change. It also allows traceability as to where accesses are coming from (auditability). If everything is using the same client-id+secret (or usn/pwd), you don’t know which ‘client’ is doing what.
Now install tools that are only available as github released binaries. And ensure that hashes match for that. Maybe install a tool that needs to be compiled.