I'm not a Green Hornet maven, but it's my understanding that Kato was "just" a courageous, capable companion and helper to G.H., and who indeed had as a primary duty driving the B.B.
For a variety of reasons, the TV production was glad to hyper-up the martial arts fisticuffs (karate was the discipline of the day, I recall) and it makes a kind of entertainment-business sense to take any Asian character and have him kick and eat noodles. This aspect was later spoofed occasionally when Asian-genetic characters in a comedy would be expected to kick a bad guy and say "What you talkin' 'bout?"
I have no argument with the TV Kato, really. What bothered me more were the "plastic" masks; they looked plastic anyway. And naturally I expected cloth masks like the "real" GH and K. Similar to the Batman of the TV show having the masky-part of his cowl formed of a stiff material and even having what in a cartoon drawing would have been ink lines painted in with white paint. Sort of jarring, and ever-present as TV shows show the the face a lot.
I'll tell you what the Bruce Lee Kato being a karate expert makes me think of: The Charlie Chan character in "Murder by Death" immediately chucking his Charlie Chan suit and putting on a Fu Manchu "gown" and cloth cap! it's okay--but WHY?
