To use free earnings to gamble at FreeBitco.in isn't a good idea in my opinion. You will need to claim a lot until you have a decent bankroll to start gambling, unless you are very lucky and hit some nice prizes like 0.002-0.02 BTC.
It doesn't worth the risk to play with a small bankroll. You won't make much profit and you will be risking your money a lot with high house edge...
And then, all your progress claiming satoshis for days, weeks, months will be over. Better to let it generating passive income.
There is no guaranty that you will make money even if you play with either decent bankroll or huge bankroll because in this game you must need a luck to make money and particularly this site has got higher house edge 5% so your chances are even less.
If you just want to play this game for fun then it doesn't matter and you can play with any bankroll to spend your free time but not for making money.
On short term there are more chances we can make more profit with a bigger bankroll, with a bigger base bet. Anyway I agree with you, more chances aren't a guarantee of profit and on long term it won't make any difference... The risk is part of this game, but sometimes we should think what is better: to play several sessions with a relatively small bankroll or just one session with a decent bankroll?
Just taking the opportunity, many people complain about FreeBitco.in's house edge and FreeBitcoin's team likes to open promotions often, wouldn't it be possible to decrease house edge sometimes? Maybe for 1-2 days, like RP promotions for an example...