It didn't say something that relates to my real daily life, only something real. Anyway, 0°F is the freezing point of brine at sea level. That is relevant because our blood is essentially brine, if we want to stretch things. The freezing point of water at sea level isn't exactly useful unless we're working with water at sea level.
Integers are easier to write. We never have to use decimals with F since we have plenty of integers. Yes, you can use decimals, but we're discussing ease of use. If you can't recognize that not needing them is easier then you're not being honest.