The biggest benefit of selling to a cash buyer is that the process is much faster than selling a house in the traditional manner. You don't have to wait for a buyer to find you, instead, you contact a buyer directly. Then you get a cash offer, and since the buyer doesn't have to worry about financing you don't have to wait. Typically speaking a cash buyer can help you to finalize the sale of your home and get the closing paperwork done in as little as a week.
A cash buyer also won't usually require any repairs done to the home. If they have any concerns about it they will convey these concerns to you, and the offer that they make on the home will reflect these concerns. While this may end up in a slightly lower selling price, it's still a far better option than having to pay for repairs up front.