I agree with you regarding the size point. There's a certain enjoyment that comes out of a smaller set-up that you don't get shooting with a large zoom. It's the reason I use the Loxia 21, and RX1RII a lot, and never use my 24-70II. It's also the reason I haven't run out and bought the 24-70 GM already, even though I really should be using a native lens for events.
Yes and no. For size, yes. But only if you take one or two primes with you on an outing. I have the bad habit of taking 4 or 5 with me, at which point the weight and size advantage goes away. All of a sudden I'm carrying just as much weight, only I also have to fumble around with swapping lenses after every other shot.
There's something to be said for a zoom in that situation.








