30 seconds is the complete user flow to open the app, select a drink, approve payment with face id, and dispense the drink. Maybe a few seconds longer in the end than paying with Suica, but pretty negligible.

And a lot of coke machines in train stations, service areas, etc also accept Suica if you prefer (but then you don't get the stamps).

Typically the machines I see which only accept the Coke ON app are in more rural areas that traditionally would have only accepted cash. And I much prefer the app to cash.