Welcome to Computer Science 101, where 256 is about as "oddly specific" as saying water is wet. For the uninitiated, 256 = 28, which means it's the maximum value you can store in 8 bits (a byte). It's literally the backbone of computing.
Tech journalists writing "it's not clear why" is like watching someone puzzle over why we have 60 minutes in an hour. The real mystery is how these people got tech writing jobs without knowing binary basics that any first-year CS student could explain between energy drink chugs.
Next up: Breaking news! Scientists baffled by why computer storage comes in powers of 1024 instead of nice round thousands!