Yep. Basically what Dary said. There's an idea in web fiction that quantity = quality (primarily espoused by the audiences). This is, of course, not entirely true. Your average novel has chapters between 2000-4000 words and, typically, there's no part you can cut. For a lot of serials, there's heaps of things you can cut.
If a web fiction is doing updates that go beyond 4000~ words, I honestly need to be able to see why. In my opinion, the art of writing is doing the most you can with the least amount of words. When you don't, you get 20k updates where people wonder 'why is nothing happening until the last 10% of the update' or 'why is there so much navel-gazing'.
On one hand, it's great that when you write a serial you're not constrained by paper or word count. On the other, just because you can write a 3000-word fight sequence or spend 5000 words on a dialogue sequence, that doesn't mean you should.
When I first started reading web fiction several years ago, where I read Worm the first time, I honestly wasn't reading much else. I hadn't really read novels in years because I was busy with a draining job and a Masters. But in the past two or so years, I'm back reading novels and, honestly, it's really hard to get into a lot of web fictions.
You could argue that it's unfair to judge a serial like a novel, and I'd probably agree. But at the same time, given that every serial inevitably tries to jump to being published (sometimes without much in the way of editing, oof), I think it's a fair criticism. When it comes to turning a serial into a novel, I honestly think it's no different to turning a novel into a TV series or a movie -- it's an adaptation.
(Worm, for example, isn't a series of novels as it stands. It's one very long first draft. The simple act of turning it into a series of novels would constitute a pretty heavy edit/re-write. For example, you'd need to create full stories and arcs within each novel, for both the plot and Taylor.)
I like to think I avoid the 'updates for the sake of updates' issue by staying a good dozen updates ahead. But that's difficult, too.