They have their own place but a majority of the time I think they're mediocre at best when it comes to the fiat economy, and in the crypto economy they multiply the amount of risk they are taking on by many orders of magnitude. Considering that every single market within the crypto economy is incredibly volatile and often, at best, a profit-maker for a week or two before becoming a relic of the (recent) past, they have to be vigilant and active with the control over their assets, since situations can change rapidly.