It may not be dropping in USD, but it is in BTC, which is the currency we are investing. It makes no sense to talk in USD terms when we are investing in a different currency.
Your previous comments implied that bustabit was losing popularity and I want to show you that that's not the case. It makes sense to think in terms of purchasing power (or USD as a proxy) when discussing the wager volume because a large number of bustabit's players need to purchase Bitcoin in order to gamble. A player that is used to spending $10 a month on gambling won't suddenly starting spending $30 on gambling just because the price has tripled, for examplehe'll just buy and wager less Bitcoin instead.
So while investmentslike betsare denominated solely in Bitcoin, you cannot discount that the price of Bitcoin directly affects the wager volume.