[VivaLaPanda]

They already have. https://support.google.com/reserve/answer/7514650?hl=en

Coverage is spotty. It's crazy how much people here underestimate the lack of willingness of many business to use these systems. I live 45 minutes away from SF and recently got a haircut at a decently popular place and it was cash only. Adoption of new technology by small businesses is really slow.

[froindt]

I agree with the sentiment about slow adoption, but in this case, it might not make sense to switch.

If it's decently popular and is fully booked, going cash only would reduce their costs and either give them healthier profits or let them charge less. Most businesses accept cash and card, so they likely already have the daily task of taking money to the bank or having it picked up by a secure truck.

[AlexCoventry]

I'd suspect a cash-only business of tax evasion before technophobia.