I actually used it a fair bit after I bought SoulSilver. It didn't incentivise me to walk more than I usually did, and I made sure that I kept it hidden somewhere that no one could ever see it, but for a week or two it was actually kinda cool. I think I got some items out of it that I ordinarilly wouldn't have done, and maybe levelled up a few critters. In time, however, its gimmicky nature became more apparent; I stopped putting it in my pocket and walking around, and just stuck to the main game. It was a nice accessory, but that's all it really is, when push comes to shove.