I came up with a legitimate use case for this feature just last night. I was trying to find more information about a particular bug in No Man's Sky related to Derelict Freighters and I stumbled upon a bug report thread which is reportedly monitored by Happy Games. I searched that thread for "Derelict" and discovered about thirty other people appear to have reported the same issue. So (counter to my previous comment) I decided that it would make sense in this context to go ahead and add my own "Me too!" to the thread, and I noted in my comment the number of times that Derelict issues have been mentioned -- and while I was at it, I also thanked the Reddit developers for adding this search feature. (I figure the chances that those Reddit gurus ever actually see my comment are pretty low... but you never know!)
So yeah; I'm definitely seeing the value of this addition.