Except you do care. That's a lie.
Without a price and exchange in the real world you cannot know how much the person is actually charging you.
If you come to my bakery and want a loaf, and I say great, I now take only momero. You say sweet, how much, I for you, only say 1.5xmr!
Do you buy the bread? If so, was it a good deal? If not, why?