If you don't need it, you don't need it. But for the record:

a) Porting your number takes about as much effort as moving between mobile phone providers

b) Setting up a sip app on your phone is trivial (server, username, password) - I'm generally a fan of Acrobits Softphone

c) My voip provider has an sms <> email gateway, so my bank (and other sms based) mfa lands in my gmail inbox