Yes, you can make an app or sell a widget without supporting transactions via mail, but many companies providing critical services are starting to require cellphones to participate.
https://www.fcc.gov/general/lifeline-program-low-income-cons...
This use to be limited to land line phones. But now is expanded to cell phones
It’s much cheaper than physical infrastructure.
But do you expect Amazon to except postal mail and work like the Sears Catalog?
This is great to see. Yes, assuming it is implemented well this is better than the sears catalog.