Wow, 10 btc for free and that also without doing anything? I will surely sell 5 btc instantly and convert it to fiat and buy a bike with that money and will take my girlfriend on a ride.
Nice plan pal and we would surely convert it to fiat since its free anyway but there are really people would tend to keep it and put up to some investments to make it grow more. 10 btc would be decent enough to make investments and also we could buy our wants but its wise to made such decision on long terms.
Converting is always available, you can do it anytime you want, but once you have converted and spent them then you wont have the chance of growing their quantity which is only possible by investing, and 10 bitcoins is really a great amount to be used as a capital in an investment which can easily grow the sum in a month or two, and after that you should convert the profits you have earned.