These things are really hard to get from someone doing a several minute video. That said, I do pretty much what you said (although I just pick one of the first page results, since I don't seem to get the 'ecelebs' (?) you get.)
Although, once I read a review of Jak and Daxter II, and the reviewer said it was fantastic up to a particular point, which was impossible to get through, and thus it ruined the game for him. So when I played it, I kept waiting for this unbearably difficult bit... and made it all the way through the game! I went back to the review, and (having played the game) recognized the area he was talking about. It was slightly difficult, in that it might have taken me three tries to get through... :-)
I watched some random streamer with 3 viewers play Skyrim an hour or so a day for several days, asking him what he liked/disliked about it, before purchasing it.
My process is typically to look at a gameplay video (as you suggest) first. If the game looks like something I might like, then I check if ACG did a review. Gameplay videos alone aren't enough. They show you a quick snapshot of the action, but it can be super hard to see how much fun it actually is, how good the design is, how well it plays out throughout the course of the game, if there are any bugs, glitches or gotchas, what the overall writing is like, if the graphics or sound are consistently as they are in the gameplay video, etc etc.
Its a good starting point, but its not enough on its own.
Having said that, I have not made a purchasing decision based on more traditional reviews in a long long time and don't personally find "magazine-style" reviews (or their video counterparts) to be useful at all.
A good review gives an accurate impression of a game's strengths and weaknesses in 5 minutes of reading. I've bought games based on overall negative reviews before, because the writer was even-handed enough for me to judge exactly how my tastes differed from his, and see that I could live with the bits he hated and love the bits he thought were just decent.
> here's a great big pile of streamers who've been playing Dark Souls for thousands of hours, and you will get a very very wrong impression of the game's difficulty if you just watch them.
Hell, when I play dark souls now, I just kinda ignore all the enemies. They're like flies that get swatted if they get too close, but that's it. This is NOT the experience a first time player will have. Instead of flies, each enemy is an angry bear with a time bomb strapped to its back, with robot claws. Every enemy strikes them with fear and apprehension. All of this goes away as you become accustomed to the game.
When you watch an experienced player play, you obviously see the former and not the latter and what you see is NOT the experience you will have. (Although, you can of course watch a video where someone new to the series is playing... but the majority of videos are by existing fans)
Go to YouTube and search for the title of the game followed by gameplay. Example: "cold steel gameplay". Now go to page 3 of the search results to make sure you're NOT getting advertising or ecelebs. You're looking for that random guy who is just recording the game. And doesn't talk. Very important detail. You want that video with sub 100k views. And now you can see for yourself exactly what you will get and can make an informed purchase.
But I suppose its just one of those things people want to do that has nothing to do with practicality.