I don't think that people participate in lesswrong to gather karma. They generally participate primarily to have conversations about rationality or other topics that get discussed on this website.

What do you mean with "real life"? I recommend "real life" rejection thearpy, because getting rejected online is easy and thus no good training.

I don't think that online discussions don't matter. Participating on lesswrong can give you useful knowledge that matters a lot more than your lesswrong karma score. I also do believe that ideas matter and that it matters to convince others of ideas.