If you're referring to just paying the winners you'd need at least 5 BTC in order to catch anyone's attention, especially those who bet big.
5btc is not enough as a bankroll especially if it is to catch attention from real gambler. 5btc bankroll means that the highest allowed profit per bet is only 0.05btc assuming that the site is using 1% of the bankroll.
A site with such low bankroll will not gain good attention except from small gamblers who usually bet just few thousands satoshi every bet. 50btc for bankroll is good enough but it is still be considered as low bankroll compared to other popular gambling sites.
own gambling site due to that low capacity.Starting up small isn't really a bad idea yet if they would able to pull out to get some players
on that early stage or even on a limited low bankroll phase they will able to generate income and would adjust later on.The only question
is,if they would able to sustain it through.