Maybe not so silly
Part of me find the idea of a fitness tracker for dogs silly, I mean really, if they are a bit chunky send them out to run around or something. But if it could be combined so I know where the little dog got to when he burrowed under the fence, or monitored the health of my ailing pet so I could give it the right medicine at the right time to live a few more months, I know loads of people who'd be willing to do that. Toward a pet's end, it's hard to let go and if there had been something to help mine live a little longer, have her feeling a little better, then maybe not so silly after all.
However on simply the fitness tracker, I'm having a hard time finding a reason for it. Would it come in handy training rescue dogs or show dogs or something?