More than 200 hotels already on this website. Wouldn't this be much more useful as an OpenStreetMap tag so people can find and share these good/bad hotels in whatever front-end they like?

There does not seem to be a tag for it yet. That there are apparently hundreds of instances, and it being definitely something you'd want to select for, makes me think it's a good fit for OSM. Currently, hotels can already have tags like phone number, reception opening hours, WiFi fees, etc. It might even be a good fit for the toilets:* namespace, since this has overlap with toilets in (semi-)public spaces offering different levels of privacy

You can't put affiliate links in OSM tags.