There are many things that elevate ao3 from Wattpad, one of those is filter and tagging. Though yes Wattpad would have this system of tagging(you'll see exclamation marks between two words), it isn't nearly as good as ao3's where in you could filter in and filter out what you want to read. Ao3 is also a website run by volunteer, though they do ask for occasional donations that is purely voluntarily by its readers, Wattpad is completely incapable of being used without subscription due to its immense, multiple, and horrendous ads(like every chapter there would be numbers of indefinite ad). In terms of being offline, you could always turn a fic offline in Wattpad, but there's always a limit to that, I think it was 25 fic but not entirely sure, nevertheless, ao3 allows variation of ways to download fics such as epub, pdf, html, and such. There's more but these are just their most obvious and primary difference when you're a reader:>>

Since AO3 is down is Wattpad really as bad as some describe it as? I'm fairly new to fanfics and novels so I don't really know who to trust with this kind of info lmao