The rewards on posts incentives the content creation. In the same way voting on comments incentives the debate, incentives feedback.
For this reason I think it is a good idea.
One example. Generally, I upvote the comments on my posts (only good comments). When the people realize that, they will start to give you more comments, comments with proof-of-brain, and this is good for the ecosystem, more discussion, more content creation ;)
I think I am going to see the whole thing a bit more relexed. Thanks.