If someone will invest 15BTC in that bot how long will it take to recover his investment, and what's the odds to see the bot losing all the balance? i mean, it can't always win, there should be a braking point.

This is a betting bot, but it doesn't have a money strategy — meaning, how could someone put 15 BTC into it and immediately start winning? Don't you think the site would ban it because of too many wins? The amounts should be small, and separate VPS servers should be used. It talks about return on investment — maybe the amount can be returned within 15 days using several VPS instances! My point is clear: someone who is a player knows how to use the bot to get the most profit.