I bought a piece of 1.5 inch stiff foam to try to fix a sag in a bed. It didn’t work but having that thick piece of solid foam around has been a life saver.
Need something flat to put a laptop on? Throw it on the foam. Going to be doing something that requires you to be on your knees for a while? Get the foam!
It went from stupid purchase to something I’d gladly replace if it broke.
The heated ones need power. They preheat the water.
There are some you can connect a hot water line to them, but with a tankless hot water heater, it could be a few minutes before hot water is flowing through the bidet. On a winter day, so that would be rather uncomfortable, I would think.