I'd like to think that if it's being used properly, it's mostly a feel good thing and people don't need to take too much stock in it. However, if somebody has contributed to this forum, which is sort of a "club", significantly due to amount and quality (or more accurately amount of good quality) of content they may have a long "rep bar" and you can hopefully expect to know their posts are overall level-headed.
The other thing that I do think is important is negative rep mostly to notify moderators of spammers or truly, truly inappropriate content (like hate speech).
To me, here at rbr when somebody says "would rep you if I could", it's just a common way to say nice post. I don't mean to offend anybody like rudge66 that may have had a rep-related negative experience.
Honestly I think what makes the rep system most useless is that limiting of multiple reps from one member to another. Maybe if the system is neutered to this extend they shouldn't have it at all. On the other hand, if you can pretty much only rep "newer" people it could be considered a guide from more experienced posters to newer ones.
I know this isn't the topic of this thread, but wanted to reply since my comment started this tangent.
