You have three issues - yeah, the pump doesn't use that much power, but it does use power. If you're trying to reduce electricity consumption to the bare minimum, a tankless water heater right at the tap will be slightly more efficient. It doesn't have to always run, but for people that don't have predictable schedules, that can result in my wasted water. And your water heater is going to have to run more, because even with insulated pipes, you'll be losing some heat as the water circulates.

It is absolutely better than running the taps wide open until you get hot water, especially if you live in a place with limited water availability. I wouldn't use my solution for anything other than new construction due to the cost of running so much new wiring.