There’s nothing very “great” about it. It’s just that they use Naver like we use Google. It has a lot features google has, like Maps and Translate. And they use Kakao Talk like we use WhatsApp. And I think Daum Cafe is the equivalent of Discord.
I don’t see any point in signing up unless you’re at least a little fluent in Korean, because almost everything happens in Korean there.
Personally, I use Naver’s V-Live(YouTube equivalent) because kpop artists go live and post stuff first there.
I also use Naver’s Papago because it translates Kor-Eng and vice versa MUCH better than GoogleT… it also has formal/informal speech settings, sentence examples, root words, synonyms and compound words for every translation, so it’s more informative.
If you’re visiting Korea, you will need Naver Maps. If you want to practice Korean, you can use the children’s version of Naver (jr.naver.com) for easy stories, nursery rhymes, animations, games and videos(you should be able to read Hangul). Everything is incredibly cute 
I love Junior Naver’s design. It’s like a complete kindergarten experience.