Flog and WizofOz, you two make good points. It makes a lot of sense if your flying between city pairs that are not covered by the RPT's.
Having said that I flown a lot of people between major city pairs such as New York and LAX. Why would they go fractional when they can buy a first class ticket on a RPT for so much less?
Less stress - your limo drives you out to the airplane - we load your bags, give you a safety briefing and 10 minutes later we're departing. At the destination, your limo meets you plane side and your on your way.
Privacy - during that 5 hour flight from New York to LAX you have the plane to yourself - a very productive environment.
Service backup - as I said above - your plane breaks, we guarantee a recovery within 4 hours - very often its way less than that. A lot of fights I do have an aircraft standing by in case I break.