Why not automatically award the bounty to an explicitly accepted answer?

Question

I've read the FAQ, the blog post announcing the decoupling of bounty from answer accepting, and many of the questions here relating to bounty, but I still haven't figured out why this bounty system works so non-intuitively.

Here's what happened recently:

1. I asked a question on StackOverflow
2. Having received no answers, I added a bounty.
3. Someone provided an answer.
4. I accepted an answer

Why would I not expect that in my accepting of that answer that my bounty would automatically be awarded? Luckily, the answerer notified me that the bounty would expire and only give him half (!?).

I understand that:

• Others can now offer bounty on a question they didn't ask – it makes sense that bounty would have to be manually in those cases.
• Bounty can be auto-awarded when it expires.

However, I don't understand why with what seems like the most common scenario, we wouldn't auto-award the bounty to the answerer of the actual accepted answer. What is the purpose of making it more difficult to do what is obviously intended?

Note: I didn't notice this popup reminder or maybe just didn't realize that the bounty system had changed since I had last used it. This popup should make it clear that "you haven't awarded your bounty to this answer" which is not intuitively obvious, which should lead us to question why awarding the bounty is a separate step.

Answer 1

From the Help Center:

If the bounty was started by the question owner, and the question owner accepts an answer during the bounty period, and the bounty expires without an explicit award – we assume the bounty owner liked the answer they accepted and award it the full bounty amount at the time of bounty expiration.

Unless something has changed and the help center hasn't been updated, the full bounty amount, not half, should be awarded.

Answer 2

Because bounties serve more purposes than just awarding the accepted answer.

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Draw attention

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Reward existing answer

One or more of the answers is exemplary and worthy of an additional bounty.

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I suppose one could come up with some sort of logic matrix to automatically award bounties based on the reason chosen, accepted answer, upvotes, etc. but I think this would cause more confusion than benefit.