the lotto may not be the best solution for getting participants, however, it does have its benefits.
the cost of entering the open last year was something like $125 per event, so in having a lotto it allows for the possibility for people interested on skiing the tour determine how much they value their spot. For some, they might not want to drop $125 to ski the open, but could afford to risk $30 (just to get a spot).
yes the lotto allows for luck to play a role in the selection process, but while you can better your odds, there is no guarantee that you will get a spot, and therefore the luck is random. Random selection provides for the fairest opportunities for an "open" event.
there isn't much difference between entering the lotto and not getting a spot, and having a spot and not winning -- both are a game of chance (one requires luck while the other requires skill.)