The freezing point of water is indeed one reasonable origin point but the temperature at which water boil (at sea level) isn't very relevant to most people's day to day experiences much less having a nice interval between the two points. You have to use Kelvin as an absolute scale for a lot of scientific and engineering calculations anyway although it would be pretty silly for day-to-day use.
I'd argue that boiling water (or water-based liquids) is something we encounter pretty often in day to day life (eg. while cooking, brewing tea, ), making it a reasonable reference