It's not for 2fa that phone numbers are required. It's to deter spam accounts. Though, if sim-swapping is too costly to do en-masse, then I guess it might be a

It's not for 2fa that phone numbers are required. It's to deter spam accounts. Though, if sim-swapping is too costly to do en-masse, then I guess it might be an effective 2fa method for an average user. But not for ones likely to be targeted.