I've never used a mirrorless camera (apart from my iPhone) but I'm intrigued by the new Nikon Z7. I currently shoot with a D800, and nearly all of my work (mainly people-based) is lit with multiple off-camera flashes, in the studio and on location.
Is the mirrorless concept useful for this type of shooting? Some of the touted benefits - e.g. a WYSIWYG viewfinder, and IBIS - are presumably irrelevant in my scenario. So what can mirrorless give me that I'm not getting with an optical viewfinder?
The main thing I've garnered from reading a lot of the marketing material, is that mirrorless might provide a more efficient way for nailing focus on people's faces, especially if they're towards the edge of the frame. That in itself might be worth the price of admission (I find the D800 very cumbersome in this regard).
Or is an optical viewfinder the way to go for a flash photographer?