Without speaking for you, is it the fact that it could be triggered accidentally (though rather unlikely) that makes you feel it’s less secure?

As far as the technology goes, it’s the same as using Apple Pay from your phone which is pretty secure. So the only difference I see is the lack of biometric with each instance of using your watch, though it does require your PIN or phones biometric each time it needs to be unlocked, it just effectively keeps that token until the watch is removed from your wrist.