[TomW]

My guess would be that gutters generally aren't necessary where the soil is porous such as Florida's sandy soil. The water doesn't pool and create a wet area. Up north, with more loamy and clay soils, the water will pool or run to a low area and generally must be drained away in urban areas through a stormwater system.

I think the gutters at the entry in TV are mainly so you can go in and out of the house without the water running off the roof showering you.