There is currently a nice discussion on slashdot (as far as discussion can be nice on slashdot) about the usage of video game stats. I am interested in them because it can be useful for players' behavior analysis (to some extent).
"In almost every new multi-player game there is a way of keeping statistics about the games that are being played. Whether it's fan-based services or a service created by the game creator. Unreal Tournament 2004 can write nice HTML files for you, Bungie keep an insane amount of stats about games played over X-Box Live. For my favorite shooter - Enemy Territory, there is an application called Enemy Territory Teamstats and I wrote this little script to keep track of my games. Are stats any important to the average /. reader? Is it interesting how many times you shot 1337h4x0rg4m3r in the head, or is winning all that counts? Do you even want people to know if you lost 14 games in a row?" (...) Its interesting to see how your performance changes over time, and what metrics you can use to measure it (accuracy, kill/death ratios, etc). There are also stats that have entertainment value, like who killed you the most, and what your favourite weapon or map is. As well as in objective based team games, stats on how many times a player has done certain objectives are nice to know - eg flag caps, bombs placed, tanks destroyed, etc. I'd often track my own accuracy stats in Quake 3 deathmatches, and even though the correlation between stats and 'winning' is only so deep (debatable to say the least), it is rewarding to see yourself improving over time.
Stats are also good for server admins, who can use them to track average player patterns. Times when player numbers are at their peak and most popular maps come to mind as useful stats to know, for managing server load, default map rotations and the like.(...) Successful marine teams will typically will play in very tight cooridination, and individual contribution to kills is not important to the bigger picture. Not having stats there removes a big part of the temptation to go totally rambo which is going to usually be bad for your team. Who cares if you are killing a bunch of aliens if you are doing it in the wrong place and your team is losing all it's equipment?
The alien style of play on the other hand is much more swarm everywhere. The aliens basically want to inflict as many kills and cost on the marines as much as possible. Raw kills is a valid way to win the match. Having the killboard then makes sense, as it drives competition between the aliens to accomplish this. There is a support alien type that suffers from this scorewise, but you usually only want a level headed person playing that role anyways, so they are probably not affected by pride games.
Basically, I'd say that individual stats are going to often be bad in games that are trying to emphasize on teamwork, and are totally sensical the more individual deathmatch oriented a game is.