Great question. I think I'd say the big difference is that people, for the most part, aren't putting their/others lives in Garmin's hands when they use their devices.

That said, I think they have some hiking/trekking oriented products which could cause problems if you were relying on them.

The headline "electric car fleet hacked" is a lot scarier than "smart watches hacked".

Then again, maybe people really don't give a shit about this stuff, and these bounties are priced correctly.