Only in that case when we play on dice site than there is chance to get busted, only big whales can win in long run as they have very large bankroll, but in sportsbook and poker we have totally different method and people can make good profit in long run.
Yeah your right its hard to make a large profit in dice if you just deposit a small amount and yeah if you have a high bank roll most them can make a profit.. but sometimes they are endup losing because they are greedy..I'd say that your bankroll should be at least 10 million times greater than your bet.
So for a "safe" long run betting system with a 1 satoshi bet you need 0.1 btc.
Just don't be greedy and don't look at the bets because it's fucking boring and you'll be tempted to make higher risk bets. I know this from experience.
I only lost money when I was greedy and stupid to think I may do better than the boring strategy. Stick to the boring plan and you'll make a small profit everyday but a huge profit in the long run.