Suppose the bankroll is 100 and the daily betting volume is 100. Over a 365 day year, 36,500 will be gambled and with a 0.5% HE 182.5 will be won by the bankroll. This is a 182.5% return on the bankroll.
Isn't this still off by 3.33x?
36500 bitcoin gets wagered @ 0.5% HE, then investors have to pay the app a fixed 91.25 BTC, and a have to pay a fixed 36.5 BTC to MP itself. So that leaves investors with 54.75 BTC in EV but all the variance of fielding the bets.
My understanding is (this may be incorrect), that MP will take 1/2 of the HE between their own commission and the app owner commission, and 1% HE seems to be pretty standard to me.
On top of variance, there's also some other conflating factors: both other investors (you should probably expect to get diluted over time, unless something goes really wrong), and players (not every EV is created equal. How someone bet *does* impact your expected final bankroll).
There is also the possibility that the owner of the casino is able to get betting volume growth to be greater then bankroll volume to be greater then bankroll growth, which would have the opposite effect as the above. IDK if there are any reliable stats/theories regarding what to expect over the long run about bankroll growth verses betting growth. tldr; Don't try to predict how much you'll make 
I would disagree with this. A bankroll investor will need to risk the possibility that a casino operator will run away will the coins in the bankroll, that the seeds will somehow leak, allowing someone to cheat, and drain ~the entire bankroll, that the coins are otherwise stolen from the casino and the operator cannot afford to cover the cost of the theft, among other possible risks. In order to measure how appropriate it is to take these risks, a potential bankroll investor will need to know how much they should expect to earn by taking these risks. There are other investments that a potential bankroll investor can make (eg investing in a company, lending for margin loans on an exchange, investing in the stock market), and an investor should invest his money in what he believes have the best risk/reward proposition.