My the vest I bought, my expectation of it is to just give a bit of extra comfort vs. part of my core clothing that I use each year to stay warm - kind of like a heated seat in your vehicle, you do not rely on it to stay warm, but it is nice to have it on.
People that have heated seats on their sleds say they would never not have it now that they have been spoiled.
This was from 2007, not enough drawing power to continue.
https://www.supertraxmag.com/press-releases/ofsc-go-snowmobiling-show-this-week/
I was present for the show as well!