I have zero knowledge about lenses and optics in general, but found it interesting that the outer edges of the frame are often blurred in a peculiar way. Was that a stylistic choice?
It's the anamorphic lenses. It's become something of a look recently so I think of it partly as a deliberate stylistic choice. But also an accident of a particular lens geometry. They just don't mind it.
Any odd blurring, distortion, or vignetting you might find around the edges could be caused by anamorphic lenses. Vignetting is often also added in post.
