Accepting sats is the easy half of a vending machine. Everything around the payment is the hard half. A vending machine has no chargeback, so a jammed coil is a straight loss. The operator needs a refund path: an LNURL-withdraw code on the receipt, or a way to pay the buyer back, and the protocol does not hand that over for free. Connectivity is the other tax. A snack machine turns over small change, so a full node on site is overkill. Most of these run a hot wallet or a hosted node, and a vending machine can be unplugged and carried off, so the float is the real risk. What matters is not the till. It is that the machine can hold a balance and pay out without a bank.