Some investors tend to gravitate towards hiring an advisor/investor because they are scared of making those investment decisions themselves. And if their investments go south, they can shift some of the blame off of themselves and towards their advisor. I've read that by the time you put in all the research required to hire a good advisor, you just about learn enough to do it yourself (Michael Kitces).
The investor has to dedicate lots of time and effort to be competent enough to invest. But the savings is lots of fees and commissions that you would have to pay someone to do it for you.