There is a real risk to giving a company your phone-number for SMS 2FA. That is that the company might, at some point, use the SMS as a single factor. This has

There is a real risk to giving a company your phone-number for SMS 2FA. That is that the company might, at some point, use the SMS as a single factor. This has happened a few times, sometimes it requires social engineering. In general, the risk is there. Combine this with the time Facebook started using the mobile phone number for more than just 2FA (suggesting friends IIRC), and there is a decent argument for preferring plain password over enabling SMS 2FA.