MFA (a better term IMO for this) has nothing to go with phones, per se.

It’s just about reducing risk by adding more proofs that the person claiming to have the right to do something has indeed the right to do something.

Unless you have excellent password hygiene (long, random, different for every single site and service) the likelihood of having an account taken over goes up quite fast. The overwhelming majority of the population doesn’t, so forcing a second factor is a good way to limit damage.

If you don’tt like the multi step process, look at psskeys. They aren’t perfect, but they offer nearly all the security benefits of MFA without having to go throughthrough multiple steps.