[ryanwatkins]

There are plenty of other payment methods than cash that have guards against being lost/stolen or the other problems with handling cash, but also dont have the high cost of interchange that funds credit card rewards.

Merchants take credit cards to avoid losing a purchase. Cards have such a high volume that consumers expect it and some small portion will skip a purchase if its not an option. But merchants would much prefer you pay with a store card, debit card or one of many other payment methods that dont have the same (2-3%) cost that credit cards do.