Yes, it is rational, because of the other 50% chance. Welcome to finance. If you think a 50% chance of going to zero is bad, well, wait till you find out about

Yes, it is rational, because of the other 50% chance. Welcome to finance. If you think a 50% chance of going to zero is bad, well, wait till you find out about some of the derivatives people trade. And hey, at least the value of this asset doesn't go below 0!