Stage Magic, as compared to Close-up, aims to entertain a larger group of people. The performing area is larger, the tricks are larger, and the magician is larger.

No, you don't have to believe everything I say, but I'd prefer it.

Mathematically, the ability of people to see is inversely proportional to the number of people that are trying to. Thus, if everyone wants to see you, almost nobody can.
 Sad really. 
Taken to the opposite extreme is the television special where, since nobody but a camera is actually watching, everyone else can see you - QED; at least anyone with a television.
One actual benefit of watching television shows is that, statistically, washroom line-ups are shorter. 

In an effort to let more people actually see, we stand on things that make us taller (stages), do tricks that can be seen from a distance (sometimes called illusions), use sound and lights so we can tell and show you where we are, and we use half naked assistants.
(Naked people are easier to see at a distance and cause far less retinal damage than sequins. Really!)