Re: Battery in straps
I'd imagine it's fear of having a lipo fire.
If you smack your wrist against a door jam or something else that punctures the battery pack - which you'll note, is strapped to your wrist - and if it catches fire (or at best, expands and heats rapidly), it can only be undone by the parts that are at that moment in time, on fire (or very hot and difficult to hold).
Highy unlikely, but having the battery exposed in a what by design needs to be a fairly soft and supple casing (IE the strap) would leave it more vulnerable to damage.
If we can get good capacity batteries that aren't made of....just awful materials (in terms of skin damage, fire risk, etc) then it's likely that'll happen though.