if you really dont care about your score, then it doesnt effect you whatsoever leave people alone.
Au contraire, it affects us quite a lot.
Many of us - hopefully most of us - play this game to engage in virtual combat. Score-keeping encourages non-combative behavior. Don't fight if you're at a disadvantage, you might get shot down and lose all those kills. Bail from your bomber rather than try to fight off enemy fighters, it minimizes your score loss (NB, this is a fine reason to shoot bailers). Attack an undefended field, you'll amass attack points and won't risk being shot down and losing them. The examples are almost endless.
When enough people start paying attention to score, the notion that one should "fly smart" begins to spread. After awhile, it takes on a life of its own, and actually finding an opponent willing to fight without some advantage, or a squad willing to send its mission into harm's way, becomes much more difficult. And this produces the effect that we've seen in the MAs for some time now - runners, gangers, vulchers and unopposed hordes.
- oldman