If they hand out free tickets and people don’t get anything good from them those people are more likely to spend real money on gacha since they’re “due for some good luck”. As a company, it’d make sense to do that every now and then. Often enough to hold interest, but infrequent enough to make you want to just wait for the next time. Plus encouraging people to log in means they keep playing in general.
As for the timing, though, I have no idea. Possible there’s some special reason, or maybe they just figured it’d be about time.