I'm genuinely curious, on recent threads about m4/3rds (and 4/3rds in general) there are a good many people crying out for prime lenses. I understand that a wide to normal prime is going to make a camera much more pocketable but is there any real advantage to be gained in the overall package size if you end up carrying 2-3 prime lenses rather than something like an m4/3rds version of the 12-60 f/2.8-4?

Surely unless primes are significantly faster than f/2.8, e.g. an 12mm f/1.8 there isn't much point. Is it all about size and would you intend to simply use one lens rather than carrying a few to cover the same or greater range than a zoom?

What would your reasons be for using primes rather than zooms?