So the reason why bitcoin literally has zero risk is that it will just keep going up into the right forever, until it surpasses $100 million a coin into infinity. I’m pretty sure one day it will hit 1 billion a coin. 

However, on a long enough time span, all these other alt coins, Ethereum and the like are light insanely risky and is essentially like gambling because on a long enough time span they will go to zero.