I think it comes down to volatility. People assume it's a bet with bitcoin because it drops 10-20% in a single day every couple weeks/months where as in all other markets that exist, you never get a drawback greater than 10% and that usually only occurs once a year or two. Bitcoin can log 40-50% pullbacks and still be in a macro bull run. Where as in other markets a 20% pullback is a recession/depression ensuing.