It will work but it's a pain. It's not magnetic and you have to fiddle with it to get the watch to charge properly on it. If it isn't on perfectly you get the dreaded Use The Charger that came with the watch warning. I tossed mine in a drawer for emergencies. Then got the first one I mentioned.
I have a third party charger, and it does not work particularly well. It caused abnormal heating issues with my watch, and after a couple attempts I decided not to use it again to ensure that I don't damage my watch battery (thankfully my two attempts didn't seem to cause any permanent damage to the watch). Granted, I paid $13 for this thing so maybe you'd have better luck with a higher end charging cradle.
It's $38, which I admit is a little pricey for a charger, but it will charge either your Galaxy Watch, or any Qi-enabled phone (it'll charge Samsung phones with adaptive fast charging). I use this to charge my Galaxy Watch and have not experienced any issues.