I'm not sure that the organizer of the bitcoin lottery will pay you a big win, so it's better to play state lotteries, where the payout of winnings is guaranteed by the government.
Most of the gambling sites mentioned in the OP still have their reputation at stake and it's unlikely for them to run away with the prize pool when they could make more money in the long run by hosting more lotteries.
not only that, you can join some of the lotteries on those gambling sites for free(maybe only one since I only know of freebitco.in which have a free lottery) or for a very low price.
@cryptobet24 as for freebitco.in as I mentioned which has a free lottery. in order to join their lottery you just have to claim their hourly faucet. also, on their hourly faucet, you have a chance of getting up to 5mbtc.