This make me crazy as well, in Bitcoin meetup people paying in Bitcoin are still very low and we have no capital gain tax, so nothing to report if you spend and buy back.

Same speach, always, "why spend my BTC if it should worth more tomorrow?" Why I answer: "If you have the cash to pay, you have the cash to buy more Bitcoin, if you really believe it will be worth more tomorrow, buy at least as much as you spend, buy 1.2, 1.5, 2 times more of possible, when price is going down 2-3% or more, buy in advance for your next spend. Using your Bitcoin will only make it even more valuable in the long term."

On the other end, merchants who are serious about it should offer some discount, cards cost a lot, like 4-6% minimum, cash cost as well, you must maintain change, spend to keep the cash safe between 2 working days, insure the risk of thief... A merchant accepting Bitcoin without 5 to 10% discount is not serious about pushing Bitcoin usage.