I'm here to mention that some people experience that in Wattpad it is harder to gain readership for a new account, due to the site itself is large in both writers and audience, not to mention the over saturation of some genre. It's also harder to self promo without coming off as obnoxious, as the forum is not really helpful (unlike here).
Plus, never be surprised of you see the regulation is very loose. Lots of unfiltered mature books, plagiarism, miscategory, copyright infringement (putting translation of a published book that's not your own, deadass mirroring Harry Potter PDF), and you wondered how they aren't taken down while they gain tons of readers (means they are popular and easy to search). I have contributed in reporting and taking down many works which break the Wattpad rules.
There are so many explicit works that glorifies abuse and rape in relationship, worst they're often made by minor. While some of them are hard to take down because it doesn't actually break the rules, if I find loophole that ables me to report me I'd to that. I don't care if the author is a minor, it's bad example.
About the community, in Wattpad you're more likely to find a local community that writes in your native tongue (if you don't speak English like me), and they usually exchange interaction in such language too. It's easier to venture in local scale of readership, if it's your intention.
About the notorious toxic community, while I never straightforward encountered so, I have seen multitude examples. Drama can be started easily and spread like wildfire, especially for writers who are popular and having some minions to do the dirty work. There are often people who ask for criticism, and instead call for harassment when somebody does their job properly and politely. Some people are entitled as fuck thinking that proper criticism equals bullying, some others believes that blatant bullying they do is criticism. It's quite messy; while entertaining to watch you better pray not to get involved.
The readers are also entitled, imagine webtoon reader but literally version. Fuckers are constantly screaming in your wall about the absence of update, sometimes they do it in more terrorizing way such as in threat or harassment. Some also will go into length of ridiculing and hating you, because their ship doesn't sail or the plot isn't going like what they wanted. Lucky I'm never popular enough to receive such.
While I'm glad some people have good experience, I'm saying the worst so you'll get prepared. Also please choose your community wisely, there are tons of writing communities and group on Wattpad that can help you. I was friend with trolls and popular writer; while they're very nice to me and help me improve, they opened my eyes about the rotten part of Wattpad.