The hypothetical case sounds very unreasonable because I don't believe you will actually go into the store and forget to bring money, but assuming that happens, if the store accepts payment with your request, it will be agreed that will also be agreed upon if you wish.

But really, I don't want to complicate the issue because it's just a low-value item or you have to buy it in bulk to avoid meaningless fees, like buying a hundred condoms/ 1 time, it is different from buying 1 condom/ 1 time, avoiding wasting excess fees. And actually, I haven't faced such a situation yet but I'm still willing to pay with bitcoin if the store accepts it.