Its a mass produced bearing type. Most likely the cheapest option for both devices. Optimizing a bearing for a gerbil wheel seems like the real overengineering in my opinion.
This is one of the counter intuitive things about production at scale. I remember I added factory cruise control to a Mazda 3 by buying the steering wheel with the buttons and having a technician flip a switch in the ECU. Everything else was already there.
They never made any additional changes to non equipped cara because it's cheaper to just produce 1 part or 1 configuration and digitally lock it out. 2500$ option with a 200$ fix.
Thing is, when I had gerbils, their exercise wheel turned on a cylinder of plastic inside another cylinder of plastic. I also had one that was a wire wheel with sheet metal spokes and a wire base, the "bearings" were the wires of the base poked into holes in the spokes. A gerbil wheel having a ball bearing at all seems a little bit extra to me.