Are you sure you want to delete this post?
Basically, yes. They are so popular because of just the general interest and excitement of big name college players coming into the NFL, and NFL teams gaming/playing the draft in various ways to make their team better.
So you have a lot of interest from college fans to see where their best players from last year entering the draft might land. Fun to speculate and see them move up and down the draft board, based on news, combine results, coaches interviews, player interviews, off-season injuries, tape studies, individual team workouts and meetings.. so many variables change through the few months leading up to the draft.
And same thing but the flip side for NFL fans; its interesting to see what the latest news and pundit polls points for your team's top picks. Plus mock drafts are interesting because you get to see how intelligent some analysts are. And also how little insider info most of us have, and how much many are just full of it and guessing.