Yes, just because you have a low rank, doesn't mean it will make you do bad.
Take this example:
At my old comprehensive high school, in Maths Extension 1, I was coming second and the highest exam mark they got was 41. After moving to the selective high school for a year, I was 22nd or so, I scored 46 exam mark. This could be due to the teaching or my environment but I thought the teachers were on par and do I believe the environment (lots of better students) allowed me to improve dramatically.
Bottom line: They might not help moderation-wise but they help you improve and keep motivated overall.