Another billion of bets in around 2 weeks? You must have over 723 bets per second

Yeah but you need to understand that most of those bets, probably 90% or more are not actually done by real humans.
Many people just use the autobet and bet about 1 Satoshi and hope to win big or they have some strategy in place.
In my opinion since there is a house edge you are better off betting less than betting more because the more you bet the more the house edge is going against you.
That and when they have a promotion, people usually spam the bets like crazy the win the prize. I am surprosed the server load can keep up.
Whether you bet small or big amount house edge % is same for every bet. If you bet more small bets then you may lose more house edge compared to few big bets for the same bankroll amount.
Whether it is small amount bet of the big amount but still this site can reach a billion bets very fast compared to any other dice sites and that is the most amazing part. It shows how good in promoting the site.
It honestly doesn't matter that much. Most people just play for fun, just want entertainment for their money (and maybe occasionally win). If you're a serious gambler, than maybe it matters to you....a lot. In the end, it all goes down to provably fair and randomness. You may lose a few bets due to the 1% house edge, but that isn't what causes most players to lose, it's their greed/hunger for profits.
There are some crypto-currency casinos with no house edge or has 1% edge favoring the players! It sounds absurd, but it's not. The low house edge attracts more players, human nature is greed, people'll bet high and lose everything. The house edge there can be called as a false sense of safety.