All of those things are really subjective. A selfie is just a photo of the subject in situ, and it's often more genuine than stock/provided shots used in travel marketing.

Consider also that the alternatives are heeding the hotel itself or a booking engine or a travel agent. As was said, if you're going to be influenced by someone, why wouldn't it be someone whose veneer of life you'd at least tangentially followed, someone who might typically have similar interests to you (surfing, outdoors, fine dining, etc). It might be an imperfect filter of the products being offered, but at least there's a non-zero chance that they rejected poor offers or didn't write enthusiastically about the ones they didn't love.

I think it's short sighted to write off some of this.

Why not look at an aggregation of tens of thousands of reviews? Much less likely to be bought. In the world of bots and influencers, reviews that cite the hotels weaknesses are the most valuable.