This would primarily be used for making it easier to detect cheaters that use a modified damage hack.
Look at the M16 for example, my M16 kills/hits (882/5240) ratio is 16.8% (which is pretty normal compared to everyone else that does not cheat) (Look at your own ratio as proof)
This means that 16.8% of the time my bullet hits someone, I get a kill.
It doesn't take much effort at all to find a cheater on BF3 stats, so I will use this guy as an example of what a damage modified hack looks like.
His M16 stats show 314 kills with 503 hits. 62.4% of the time he hits someone, he gets a kill.
(Because he is cheating. His bullets do 3x more damage than everyone else's. Also, look how high this ratio is for every other weapon he uses - way higher than yours.)
My point is, that it would make catching a cheater easier using battlelog, if the computed kills/hits ratio was displayed for each weapon. I believe that if it is harder for a cheater to hide, the less of them will do it.