If you don't win, what's the point of kills? Like you are just one of a few dozen of people who got killed and didn't make it to the end, no matter how good you are at killing, and you probably got outplayed by someone with less kills because they are more clever.
Also I feel like 80% of the kills people get in this game are from third partying others, so if course you are going to get kills fighting someone who doesn't have full health and shields. Then there is kill stealing from your own squadmates etc.
So while there are definitely players out there who are good at getting constant high number of kills, I just don't think they matter in BR games. If you are all about kills, there are games that are all about getting kills, why not just play those?
In BR, win the game first, then see how many kills and damage you have.