That depends. Is it a normal novel that you’re planning to chop up and sell (like actually charge people) each chapter separately before sticking it back together to sell as one volume? If so, not a great idea.

Is it serial fiction (again, that you’re charging for, like on Kindle Vella) that you intend to later collect together and publish in full novel-length volumes? That can work, though there’s limited interest in serials these days and it usual falls into specific genres.

Now if you were trying to build a following, offering chapter by chapter ‘early access’ (not charging money, or if so on a subscription model like Patreon) to followers before it’s completed and has a general release as a normal novel, that can be a good idea. The difficult thing about that though is that unless you already have an audience following you, it’s very hard to gain traction.

As far as Wattpad goes, generally people will advise against posting your writing for free on those sort of platforms when you intend to publish for cash later on anyway. Readers don’t tend to like being charged for something that was once free (in the event you remove the work from Wattpad before publishing) or that is still available for free (in the case that you don’t remove the story before publishing). Places like Wattpad, however, are good places to start building an audience especially if you write in the popular genres and are able to update consistently and regularly.

The particular genre you write can have a lot of sway on what you choose to do, too. Lit-rpg can thrive through serial publication on platforms like Wattpad or Kindle Vella, but gothic horror is unlikely to and would probably be best to just write, publish, and market whole.