this is one very specific example and it's worth considering that those scribbles are still considered storyboards they're just less detailed, this artist in specific has assistant to handle other parts like inks, colors and effects because he's got a hand injury that makes the work difficult (he's talked about it quite often on his ig)
it may not be "industry standard" but if you've looked at the credits section of any traditionally published comic book you'll see credits for pencils, inks, colors and lettering all of which are official titles. webtoons likely has people in positions where they have to adapt this where one person fills multiple roles but it's not as absurd as you may think.
it's also worth noting that many many webtoons and webcomic artists have been suffering from issues with their hands due to workload among whatever other issues so this seems like a really really odd take