I'm not willing to go as far as to completely poo-poo Youtube as a source of tonal comparison. I think in the main it can do a good job of conveying differences in audio sources. The problem is really one of taste. There are very few people who play the way I want to hear being played through this kit. That's the first major hurdle. Guys like JNC or Paul Hindmarsh (sorry both!!) are basically about as useful to me as a chocolate teapot.
But then guys like Ola or Fluff, who are far too metal orientated for me and don't use enough effects and don't actually really experiment all that much and only have like 1 or 2 sounds ... pretty much the same. Can be engaging, but I rarely learn anything.
@GuitarJon has a similar idea to cleans, crunches, high-gains as I do, and he plays in similar tunings, and he uses a lot of the same kind of chord shapes that I do. So right out of the gate, he's far more representative to me. Whereas I would guess for someone who worships at the altar of Bongelamassamassa or whatever, then Jon probably isn't
their cup of tea.
And since in these comparisons, the gear is all going through the same medium with the same audio compression and what not, I think the relative differences are what are most important.
At the same time, because you're not the one behind the wheel, a YT video can never be 100% representative. I've bought pedals based on liking what I heard in YT videos, and then failed to connect with them on any meaningful level, and ended up selling them within the year. I've also heard YT videos and not really fancied the gear until I tried it myself - actually the Universal Audio pedals are a perfect example of this. I don't know why, but very few of the gear demos gave me the horn for those, until I tried them in a shop.
I think this dichotomy is probably why we have so many guitartubers in the first place. Coz everyone basically wants to hear what THEY would do with a thing.