Problem with your codes is that you allow a withdrawal for every winning using the bonus code, you should apply a wager requirement like atleast 30x so that people could spend some time trying some games before cashing it out
They already have the chance to try out some games before cashing out, they just choose not to. You're right though, it would probably help, but it'd be too complicated and probably not worth the time to build a wager system to enforce a ratio (but still make sure the users are allowed to spend and withdraw their own coins) just to counteract greedy users.
Alternatively , you can try to do some better promotions in games and rounds sections apart from the bonus code, like top wager of the week will get some bonus BTC, or etc, this could actuaclly give your sites some traffic and more user to try it out
Decent idea. I'll try something like that eventually. Currently I'm giving out higher value codes to ID verified users on my marketplace and will post the link on Reddit (with detailed info) in a few days. We'll see where it goes. For now it's mostly just people saying it's a good idea and not playing. I don't take it to heart though. When I created BitBargain, I was the only seller for months, I had to beg sellers to log online and accept trades. Now it's one of the biggest marketplaces in the UK. I'm not saying BETwitter will definitely become successful, I'm just saying the lack of interest in the beginning doesn't mean much.