The second step to enable this smooth real-life use case of buying a coffee with crypto, would be the ability to request a payment with a specific XRP or fiat value preset.
Imagine the following scenario:
The owner of the coworking space has his XUMM wallet set up with full access. The coffee shop cashier has the same XRP address set up as read-only access. She can still request payments, and it would make her life so easy if she could simply type in the fiat amount for one coffee (for example 60 THB here in Thailand), and XUMM will produce a QR code with the right XRP amount set, according to the current exchange rate. I could scan it and pay in the blink of an eye.