I think a lot of the benefit is psychological. After awhile of lurking, people will begin to remember who the big influencers are. So when a user begins to post and see who is liking them, if some of the people doing the liking are familiar names, it can make the poster feel like they are contributing worthwhile things, which is great.
I also think it’s a nice idea to see what the big names like. But there’s probably something to be said about seeing a big name liking a particular comment could sway opinions towards that comment, which might not be ideal.