Because when the biggest gaming convention in the Northern Europe is fifteen minutes' drive away and your friends are converging upon it from three different countries, you don't have the option to skip.
Also, I get to run games. Play games. Buy games I never would have bought otherwise. Raid the bargain bins in the dealers' room. Meet aforementioned friends. Make new ones.
This year, I might also be manning the stand of my scifi club, and try to sell my new book on roleplaying games. Really, no option to skip.
And really, if you haven't played Call of Cthulhu in a non-Euclidean convention centre, with the Great Old One himself lounging around in the next room at least once, you haven't lived.