I personally don't like sitting on videos I've made simply to have them premiere at-con.
One, I'm impatient as hell about releasing them. XD
Two, I think the biggest benefit of premiering your video at a con is if you are attending said con. Being able to see your video for the first time publicly and getting that very first reaction can be especially inspiring for a lot of people.
Since I don't travel often (lol, I'm poor), premiering videos at cons doesn't really appeal to me. However, there's no right or wrong answer to this. Everyone has their preference on the matter.