Well, when I first saw this I was thinking about my son. He works in the film industry - both indies and feature films - camera work, rigging, lighting, etc. His cell phone is a permanent fixture for him, and he often spends hours outside, standing, sitting, etc. without much movement to keep warm. Whether or not he buys one is up to him, but to a point I can see the value.
Fwiw I spend a lot of time in moderately cold temps. My own preferences are for polypropylene or similar for the inner layer and fleece on top of that with a good wind layer outside. REI, Patagonia, NorthFace and Outdooor Research all make/sell great products along these lines. They sell a variety of options based on the intended use. I haven’t bought for a few years but REI used to use the term “expedition weight” as their warmest under layers. I bought some and the stuff was too warm for me. OTOH the always sensitive to cold, lady J loves the heaver stuff.
Since going this route, I abandoned using any kind of insulated outer layer other than as a really good wind layer.
A possible problem with a heated jacket is that given someone does wear layers, the jacket may be too far from the person’s skin to do a lot of good.