some qi charges will work, but not all
I'm not sure how they "lock you into ther" ecosystem, lots of other people make watch chargers.
I've got a nice combo watch charger with a leather qi pad for the phone from nomad.
It's kinda how I'm "locked" into buying appliances made for the US, since plugs from other places don't fit the outlet.
and the round puck is a great shape for charging the phone without having to remove the band,
If you've got a band without a buckle, you have to remove one side to get it to get the back of the band out of the way so it can sit on the pad. or loop the band all the way around the pad, meaning the pad won't sit flat anymore.
and on the bands with a buckle, they come out of the watch going downward so they will curve around your wrist, meaning they tend to lift the watch up a bit when set on a flat surface, possibly causing poor contact with the pad.
about once every month or 2, I don't get my phone centered on the pad well, meaning it doesn't charge overnight.
with the smaller charging "sweet spot" of the watch, I can imagine getting it lined up without the magnets would be a bit tricky.