Lets see...
You can post anything on newgrounds that is web games, animations or CGI films, musics and digital art, so you doesn't need a bunch of accounts to post these
everything here is noted by everyone, your work will always be noticed from lots of people then websites like youtube or itch.io, big youtubers and creators like Egoraptor, PuffballsUnited, Alan Becker, Meat Cannon and among others and others grew up here, you hardly going to be noticed if you post on big websites like deviantart, youtube or soundcloud, the best pieces of content that i found on those websites only got 15-20 likes while a more "mature" content got 1K (the internet is incredible)
if you like to participate on competitions or collabs you will love newgrounds because it has game, animation, music and art jam with incredible long time prizes and the collabs are so amazing that in time the collab goes for 1-2 million views on youtube the zelda cdi reanimated as a example
medals and trophies are a thing that newgrounds has but itch does not