I will hold 6 btc for future and invest 6 btc in altcoins to increase my coins for the future and even if my trade doesn't goes right then 6 btc will take care of me in future.
i think i would do the same thing, i would save half in order not to lose it all if i make bad decisions in trading and i would do trading to make profit
Neither invest all coins in trading nor sell all your coins to fiat, its always good to have some coins for the future and if you make right moves in trading then you can expect higher number of coins in your wallet.