my wife is a realtor, so full disclosure.
having seen the process, I can vouch for the value. FSBO is a great approach for some. particularly if you have a lot of time on your hands and you understand the process a bit better than the avg person. For the avg person, however, there's a lot of value in turning the keys over to an agent and having them handle the entire process for you. in a typical transaction you have to value your home (which involves a fair amount of research); photograph and market; work up a disclosure; negotiate offers/counteroffers; work up the final contract; conduct inspections; resolve post-inspection issues (which are very common), etc., etc., etc. You can make it real simple by selling your house as-is. But, you also won't attract any serious buyers unless your price is ridiculously low.
don't get me wrong, you don't need an agent for some transactions. But for others, a good agent can make a big difference. for every case where FSBO works out great, there's an equal case of FSBO not working out and the seller brings in a realtor. it is what it is.