had heated grips on a BMW a while back.
Nice to have warm hands but only your palms get warm. Wound up frequently holding the back of my hand against the grips to get them warm.
Headed glove liners would be my choice. Those on the market today have heat in the fingers as well as the palm and back of the hand. They fit under many regular gloves and when things warm up, just take off the liners.
There are battery and hard wired options.
If you look, don't forget to check ski stores or snowmobile stores too.
Motorcycle riders aren't the only people whose hands get cold.