I self-published novels for 7 years before taking a break, and then coming here to serialize one of my stories (still working on a novel for traditional publishing). I don’t think either is better, necessarily, and I enjoy the mindset of both, but I have noticed I approach them a little differently.
I haven’t been working on the serialized story for that long (though it is a rewrite of a “conventional” novel), but one thing I noticed is that writing in this format makes me a little more aware of what is happening in the story at any given time. Because the “chapter” (often a piece of a longer chapter) is so short, you really do have to make sure you lead in with a paragraph that puts the reader back into what happened at the end of the last chapter. Then, you have to get the action (or dialogue, or whatever the pain point of this section is) going quick before you wrap up with a cliffhanger that makes people want to come back.
Comparing it to a TV series is good, because it’s a lot like writing one. It’s “long-form writing”, rather than a chunk of a story that might fit into a larger narrative (such as in a novel). This definitely does allow you to add more than you would in a novel that has to be contained to 50 or 70 or 90K from the get-go, and your story will be longer in the end (whether that means, from a print perspective, that you break it up into smaller novels, or sell it as a single book, is up to you). I personally think the longer story leads to a bit more character development (or, it can), and more exploration of the world. I also like that it’s a bit more relaxed, in a way, because you can write as much as you want on a certain scene/topic/character, so long as you’re keeping it interesting.
As far as cons...well. The major con I’ve noticed is that it’s a bit more difficult to tell where the story will end/how long it will be, though, as it’s a first draft, this isn’t surprising. (On that note, you cut out the possibility for an improved second+ draft, because readers have already read the story, though you can do some edits in the “final version”.) There will, more than likely, be plenty of inconsistencies over time, because you develop ideas as you go (which means more editing in the long run, when/if you go to publish it otherwise, or put it in print form). The biggest con, though, is: OVERWRITING. When you’re working with a limit of 70k or so, you can’t overwrite. You have to cut everything that is extraneous out. But if you’re working with a virtually endless open field, you can easily overwrite, and it drags the story down.
Being conscious of genre tropes and reader expectations is good (though I always caution that you should write for yourself first). That will help you steer the story. Writing an outline of your basic ideas is good. But also, being flexible is good. Learning how to back yourself out of a corner is a skill you need when writing, but especially when serializing, and I think it’s a good place to learn it.
My advice? Have a buffer (of course). Write out an outline, even if it’s basic. Edit before you post chapters, to help with consistency (here’s where the buffer comes in, too). Pick a page/word count you’d like to stay around for each chapter. And figure out where you want your story to end. I’d also recommend reading a bunch of light novels, pretty much all of which started as serials online, to get used to the format and get an idea of how others write. You can also check out serialized stories from other writers (they’re popular in many places outside the US). Also, a lot of older fiction was serialized in magazines, so reading classics like Dickens and Sherlock Holmes will give you another perspective, too.
Really, it’s all writing at the end of the day. The mindset is a bit different, but you still want to tell a good story. And I think both methods can inform and strengthen the other. I’d say my “conventional” story has strengthened thanks to my work on the serial, and vice versa.
Happy writing to you!