What else do you need if not practice? At least for sports, that remains true.
I guess these games, simple as they may be, require common sense (something not needed in lots of sports where you just need to power through and endure), and that’s too much for your average american kid to handle.
KDA does show some measurement, if your KDA is high on the D side with certain heroes such as tanky ones or ones with decent escape (genji, li ming, for example) then you die too much. Feeders as well as aggressive divers that die far to much is frustrating. Too often those folks are the ones blaming others for there feeding.