If they had a Trackpoint version, I'd buy it in a heartbeat. I have their Thinkpad Bluetooth keyboard ][, but it occasionally has weird battery issues that require fussing with it.
That's actually a cool idea. You may just use recharge your devices while you watch a video or read a long article, instead of fiddling with a pen or a spinner. Or the mouse can serve as "it's time to take a one-minute break: do ten squats while recharging me" reminder.