some times i tought, that, if freebitco users earn (0.01%day/ 4.08Year) interest when are balance above 0.00030sats, and we can withdraw any time when we want, why don t an option to stake and lock btc on site, like lock FUN, and earn a bit more percents on our BTC balance?...
Because FUN token is their native utility token. They want users to purchase FUN to boost the price in exchange for the benefits in the casino. FUN utility will be useless if they let other currency use to be staked since no one will by and hold FUN token since everybody preferred blue coins to hold long term.
Actually, FUN token is the only casino token that I knew that gives real utility to their token since they provide different reward that involves the casino for token holders unlike mediocre casino tokens that only use as rakeback rewards or stake like DeFi that doesn’t gives much benefits for holders.