I have used this site for getting some obscure papers I would not have found on Research Gate. This is what I consider it good for.
It also does some annoying things. Its constantly wanting me to get a paid account. Then I would get some services I don't think I want (like download huge numbers of papers related to some subject, but I already have too much to read). It also sends me a lot of "hey we found a new citation of yours", but its not something I did and they won't let me see it without a paid account. Poor quality curation practice in my opinion.
They have recently sent me info on publishing (or reviewing) in a new on-line journal like thing they want to make. I would probably need a paid account for that too.
The site can more easily expose you to a wider collection of people that Research Gate might. I was once involved in an on-line discussion on origin of life there. It drew a bunch of philosophy types (some reasonable, some not), a couple biologists, and some who had some really out there ideas which made no sense to me. It made for a lot of discussion.
Summary:
Good for finding some free obscure downloads of articles.
I would keep a skeptical mind WRT other things it does.