Time was the Tight End was an extra lineman who occasionally trundled a couple of yards into a zone hole and caught a few yard check down on 2nd and short or first and ten.
Nowadays tight end stables usually consist of a good blocker a good receiver and a veteran or developmental prospect the team is trying to improve to replace whomever is older or declining of the other two. With every team bar a few searching for that special guy like Jason Witten (personally I think he's the best in the NFL) who can do both very well.
The stat is either good or bad depending on how you want to look at it. Either you like having an all round tight end, or you're happy to have an extra receiver. Either way it just shows the propensity some coaches have to use players of a certain type in certain situations.
I just found it to be an interesting stat considering his statistical performance was actually comparable to Nick Mangold's last year.