Not everyone in the US
has a mobile phone.
(10 million Americans
don’t have one.)
Not everyone in the US
wants their mobile phone
attached to every website
or email
or other online account.
Not everyone in the US
brings their mobile phone
with them
every place they go.
Mobile phones also break.
Batteries run out of power
(especially during emergencies).
Things go wrong.
Give people
another option
when dealing with your business.
(And that includes
identity verification.)