I think the high number of tickets has also something to do with the wagering contest.
Because you get 1 free lottery ticket and 5 reward points for every 0.00000500 BTC you wager.
This isn't 100% accurate because the stats are to the end of Saturday but 7 days wagering volume was 1,185
BTC. That gives 237 million tickets and is a very small part of the 1.1 to 1.2 billion total.