Why does this matter? I have no idea what 0% or heat means, but know what -18° or 38° mean. For me 32% heat doesnt mean anything.

How hot it feels can change. In summer, 10°C feels cold, but in winter it feels hot

A lot more people use °C so more people would have to relearn how temperature is measured

I dont think either of them is better than the other, its just that you got used to what numbers means its hot or cool