Saves me the bother and time of visiting many sites on a regular basis to see what's new. RSS is delivered to me.

By choosing what I sign up for, I know what I think I'm going to get and will soon unsubscribe if not. If so I miss nothing. Same reason people prefer purchases of things they know they want to be delivered to them. THAT'S "modern times" to me! You only drive to the store if there's a reason to.