If our question gets upvotes, we gain our reputation. People think our question is useful or good, so they 'award' us reputations.
If our answer gets upvotes, we also gain our reputation. That means people are appreciating us because our answer is good and helpful, or it answers the question.
However, sometimes I see some very good comments which get a lot of upvotes. They can be funny comments, useful comments, or even comments which is actually a complete answer for the question. Such comments can get hundreds of upvotes depending on the popularity of the question.
The 'authors' of such comments really deserve reputations!
So I think that should we award reputations for good comments? For example, each upvote gets +1 rep or +2 rep.
I even think that we should set bounty for comments!