Your first assumption is wrong...single stage is not the best way to go for a first time user. With single stage it is "one and done"...one time spray and whatever you end up with is what you got. Runs, bugs, bleed through, etc, etc... With BC/CC you can see what you have after you spray the first coat of BC...that leaves you time to correct any mistakes before shooting the final clear coat. BC sprays on smooth and dries fast, less chance for runs, less chance for bugs...you are in Florida after all. Once you get the BC where you want it and spray on the clear you can make corrections to the clear much more easily than you can with a single stage job. All that and you get a superior finish with the CC. As for cost, you can save some $$$ by using cheaper BC and then put that savings into a quality clear.

 

Charlie has hit the nail on the head and his explanation is perfect