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?

I agree with all your points but you need to know one thing that all these sites are running to make a profit for themselves not to distribute their hard earned money to the public. If the admin doesn't make a profit then surely he will close the site but he is running for so long even after with so many features means he is still in a good profit.
Gambling sites faucet money is not just 20 or 10 santoshi but they give a higher amount to try their games. For example, FJ gives 500+ santoshi to try their dice game.
Gambling sites and faucet sites are completely different and their purpose also different so we can't compare both of the features.