It's funny, every time I see the word "pedometer" I think of a device that detects nearby sex offenders.
The only problem I can see with this is if the pokemon automatically learn moves like they do in the daycare. That way, you'd only be able to put them on there without fear if they have already learned all of their level-up moves, and by that point, there's not really much of a point in level grinding, thanks to autoleveling. The item features sound intriguing though.