Cash app: 

1) available to 350-700 million out if 8 billion people
2) requires gov ID - billions dont have this
3) requires modern device - billions dont have this
4) requires fiat rails - billions dont have this
5) requires fiat bank account - billions dont have this
6) requires email + pw - extra friction

It may be easy for @Karnage 

Not for most of world. 

 Nostr + lightning can help with all of this.