Exactly! Sure it seems 'logical' at first sight that directions for the feet are directed at the feet. But since all signals need to go through the brain anyway

Exactly! Sure it seems 'logical' at first sight that directions for the feet are directed at the feet. But since all signals need to go through the brain anyway, I don't see why you can't replace this with a bracelet or smartphone in your pocket (two vibration patterns, should be easy to learn). Especially the latter saves you a lot of recharge hassles. Steps could be measured just as well with a clip on my shoe(s) so I can wear whatever shoes I want. I would be surprised if there is no disadvantage at all to run on these shoes (or inlays) compared to a pair of well chosen running shoes.