I took my daughter and my nephew to a con a while back. We signed up for one of those elaborate 3-d dungeon terrain games. The guy running it had great toys but no sense as to how to run a game for actual human players, nor did he know how to handle his ruleset. My daughter was deeply disappointed. Con games like that, designed to showcase a mini collection rather than provide for a fun play experience, are much too common, I think.
Four or five weeks ago, quite out of the blue, she told me I need to run a similar but better sort of game at a convention. I told her I could do that, but I warned her the minis would be less adeptly painted and the terrain more crude. She agreed to my stipulations. So now I'm once again the kind of DM who uses a tactical display, apparently.