Warmer water is good for softening oils, but once you start getting mixed food stains, hot water can cause it to congeal and become harder to remove. If you need to scrub harder to remove it, it's probably something that won't benefit from using hotter water. Remember this if you ever have to wash "mucous" out of your hair.
I think they’re more a lesson in marketing than anything else. The scrubs themselves fall apart, clog drains, and contribute to the proliferation of microplastics.