we don't want to: 12 is more divisible than 10
I don't care that 0°C is freezing for water, and 100°C is boiling for water. I am not water, I am a human. I would rather have a system that is human-centric, even if it is "arbitrary". 0°F is about as cold as you can go outside comfortably with a decent coat, and if it's 100°F, that's about the limit of what humans can tolerate too. If it's 100°C outside, you're dead, it's useless to daily experience, and to me, daily experience is far more important.
The best part is that isn't even true at different elevations. It makes no sense as a reference point for many people that live at higher elevations. What a weird thing to base a system of measurement on since it isn't constant.
0F, it's cold and the wind chill makes it miserable. 0C? That's 32F, which is technically freezing but I can still work on my cars outside in that weather.
100F, sweaty, hot, chugging water if you're outside. 100C? GG, you're dead.