petermc Hard to tell their reasons, I own the camera and usually if you see that wonky part on faster motion it usually means they only shot at 30fps and interpolated to 60fps.
Regarding the blurriness the lens itself has a manual focus ring so if they dont ensure their focus is correct anything beyond a certain distance will look blurry. Also, I'm guessing they are shooting at the widest aperture f2.8 which also has a shallow depth of filed but needs less light, I personally always try to nail my focus and shoot at f4 or f5.6 which in general has the best sweetspot and much wider depth of filed, specially compared to f2.8, which I can see people use all the time to not have to supplement as much artificial light instead.
Just my guesses based on my experience with the camera so far.