It might sounds dumb but there are really people who doesnt have the time to make their own trades and rather they do let others do the job with corresponding fee.
Come to think or to compare on handling other peoples money would be different when you are the ones who are trading with your own funds.Trust is the main issue on here
because you wouldnt know if those persons are trustable enough or not.Even if they do have high profitability on paper, i dont still recommend on using up fund managers.
Its better to lost amounts on your own that to other people.
Fund managers exists in the stock market field but the same thing is not possible with cryptos because anyone can run away with your money and its not possible to recover them without that person authorization.As you said its better to do it on their own or don't even need to do it because they can still earn by doing nothing in long term other than simply holding cryptos in their wallets.