Isn't karma just like an anti-spam mechanism that barely works?
And you get karma just by posting whatever the community wants to hear. So it's not like it shows how enlightened you are or anything.
Anyway, one thing that bothered me about Reddit's karma system, is that people would delete their comments if they got a few downvotes, even if they had something important to say.
Here on Lemmy, you can quickly see both upvotes and downvotes. So if someone says something controversial due to politics or whatever, they're less likely to delete their comment because they can see "ahh, I'm not just being mercilessly attacked, 50 people upvoted me."
That can be abused I guess, but I like that it promotes discussion that isn't just echo-chamber nonsense. We'll just have to see how it works in practice.