I think it depends on what game you're playing. Coming from the CS:S Division, some games you can focus on getting a high kill score (like in Deathmatch for example). Even so, I think it's more of a "focus on your skills" type of thing. It's not that hard to camp in a corner and kill everyone who walks in front of your awp scope. But those who can rush into the middle of a firefight armed with nothing but a silenced USP, and come out living... now that's skill.
In other games however, why worry about kills? Take CS:S Jailbreak for example. Does it really matter if you have a lot of kills? It either means you're gonna be targeted more as a Terrorist and killed for almost anything, or as a CT means you're prolly just a bit trigger happy.
That's just my opinion. :3 Have a nice day!