Why don't we award a rep point for a helpful comment that improved an answer?

Question

Background:

Use of the search feature did not lead me to any question on meta that addressed Comments earning reputation. (this addresses reviews, not Comments).

My question is based on the triangle next to a comment that (if you hover your mouse over the triangle) indicates that a comment added something useful to the post.

Having asked a few questions and posted a few answers, I have found on more than one occasion(neil slater's help on this question being a good case) that a user makes a comment that helped me improve the answer by either pointing to a new resource or a theme/concept that I hadn't folded into the answer.

While I understand "we award rep for core functions," I feel that the comment that is helpful to the querent or the responder supports the core function directly: good questions, good answers. A single rep point here and there won't break the rep system, and unless someone finds a comment helpful, it doesn't even touch it.

My recommendation is that a "this comment adds something useful to the post" flag (triangle?) being clicked awards a single rep point to whomever wrote that comment.

Why?

RPG.SE voting, now that I have reviewed about 20 questions/answers that did come up from that search on voting and rep, is biased toward up votes as a means for helping this site achieve its objectives:

Good answers, better answers, and best answers to good questions posed is why we are here.

When one of our community members provides an insight that makes an answer better, or even best, that member has helped this SE site achieve its goal of putting out good answers regarding this hobby. A rep point reward seems to fit into how rep awards incentivize participation in a constructive way.

Position contra considered:

Having read a number of meta questions regarding comments, and the problem of people answering questions in comments instead of providing answers, I can see that this might lead to fewer answers to choose from, and a worry that this would incentivize undesired behavior.

Contra to the contra:

The flip side of this is that if A's answer covers most of what B would say, but B knows a point or source that A hasn't mentioned, isn't it better that B help improve A's answer rather than post an answer that replicates A's answer but adds one more thing?

Have seen considerable discussion in meta about answers in plentitude that say the same thing being undesirable.

Maybe this question has two parts:
a. Why doesn't someone clicking on the "this comment adds something useful to the post" triangles award a single rep point?
b. Should the voting system accommodate that?

I think it should, but there may be a good reason, or some experience with this idea that I am unaware of which explains why this is a bad idea. None of this is related to the fact that comments go away eventually (allegedly). This inquiry is based on the idea of rewards for improving the in-process crafting of better and best answers to good and better questions.

Answers to this question should cover:

• This has been tried before and X happened.
  Doing this does/does not support the intent of the voting system.
  Doing this does/does not support the goals of SE
  Doing this does/does not incentivize the behavior we prefer in pursuit of site goals.
  We covered this "here" but the way you searched missed that Q

Answer 1

This won't be implemented for a few reasons:

1. We don't control the software. This would have to be altered at a very high level by Stack Exchange developer employees.

2. The purpose of the reputation system is to alter behaviour. This proposal suggests giving reputation for existing behaviour, but people are already motivated to help in comments, so there is no apparent need for reputation to spur action. Since people are already motivated, the only effect giving reputation for this behaviour could do is alter it away from the current state of affairs, likely leading to undesirable behaviour changes.*

3. There's no way to know why someone clicked the "comment upvote" button, and no way to link it to a positive change in the post. Anyone can upvote a comment and the system has no way to know why, currently. Being able to "accept" comments after implementing their suggestions would require significant new functionality.
4. There are many behaviours that are helpful to the site but don't earn reputation, such as editing other's posts to improve their quality, voting in the review queues, … or participating on Meta. ;) Not everything useful to the site needs to be rewarded with reputation — only those things that people might not do without such a bribe.
5. The proposal was made and rejected in 2009 and the reasons are unlikely to have changed.

In sum, there doesn't appear to be any need to give reputation for useful comments. People are already doing it, and gamifying it would likely interfere with that more than help, even if it was within our power to do.

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* There is an existing, parallel system for rewarding behaviours that are desirable but which it would be harmful to allow people to “farm” for reputation: badges. For commenting we have two: a bronze Commentator badge (for using comments at all) and a silver Pundit badge (for writing well-liked comments). Those are SE's way to show new users that good commenting is appreciated, without motivating anyone to make it their primary activity on the site.