Operating a btc gambling site is worth it as the house wins more than it loses. However, you need to have a large capital to bankroll in case some btc whales get lucky and win some of your btc. You don't want to face a situation when nobody is able to withdraw because of lack of btc. I am tired of seeing all the dice sites sprouting up and it would be refreshing to have new gambling games.
Agree and the owners must have much capital is for promotion the site
for example must there are money for pay Google advertising,
the other example pay members signature campaign if making promotion on bitcointalk
the promotions must be for long time until the sites are famous.