Honestly, to a certain extent, it might benefit an artist who's struggling and asking for help to remind them of BASIC art principles. Like I mean the more basic the better. Like, show them the color wheel or some human anatomy, but that's it. Once you get into the more detailed stuff, it's REALLY not as simple as "ooh this is wrong, you should do it this way instead" — it's how you get these gross carbon copy art styles all over the web and it annoys me.
I see a LOT of bad Tumblr/Instagram art tutorial posts that follow the "wrong!" "Right!" Formula and it kind of bugs me because a lot of art can't be simply boiled down simplified black and white categorization like that...
Like for example, (and this is only an example)
This i feel is kind of ridiculous. I can sort of see the point of rendering hair so it looks 3D but this tutorial is WAY too simplified and ambiguous to actually be of any use, much like a lot of the other "fixing art" tutorials. Also the whole thing with the "use a nice saturated pink to shade/tint the skin so it doesn't look gross and muddy!" Like uh, ok, that's a trick to make your art look pleasant, I guess, but I haven't met anyone who has extremely rosy, shiny, and perfectly defined skin which light majestically bounces off of.
SO much of drawing/design is a matter of personal taste and technique, which is why actually good art professors take the time to understand what falls into "fundamental practices" and what falls into "a suggestion, a technique that works".