Beside the till is the obvious spot, and for a lot of shops it's the only spot that matters. Everyone pays, so everyone walks past it.
If that's your business, one card is genuinely all you need.
With two
Not everyone deals with you at the till.
Some sit down and never come back to the counter. Some wait at reception. Some are served at a second till entirely. A card by the register misses all of them.
A second card covers one of those other moments. More places to be seen means more chances someone taps — not a guarantee, just more opportunities.
A cafe has a till and tables. A barber has a counter and a waiting area. A clinic has reception and a second desk. Wherever there's a second place people stop, there's a second place to be seen.
