There are so many sites are runnings successfully with just 1% house edge and do handle even more bets and they also run a lot of promotions then why can't freebitco site permanently reduce the house edge to reasonable one?
If you want to run promotions should run with site profit but not from players money. 5% is too much for a dice game.
and where the site profits came? players who lost their money dicing = players money
remember freebitco.in is mainly a
faucet site not dice/gambling site, feel free to claim faucet without waging your money
other sites you're referring to are a gambling site with (sometimes) a faucet, if you abuse the faucet you'll be banned
freebitco.in offers interest on your idle balance, gambling sites do not
freebitco.in gives lottery tickets when you gamble, gambling sites do not
the most important thing is you don't have to gamble on freebitco.in and use other features on the site
but what else could you do if you register on a gambling site but not gamble your money?

If it is on freebitco.in, I believe they have so many source of incomes, besides players losing, there is still advertising incomes too so I think if they can allocated their funds well enough they will be easily promoting their site as well using this funds. Btw do you even see some sites offer 5% house edge? I believe there is only one site here that offer huge house edge and that is freebitco.in and with this huge house edge they can manage their lottery sytem as well