Accepts are a way to indicate what worked best for the OP or which answer they personally liked. Sometimes the OP's choice isn't the best one - after all, many people ask questions because they don't know much about the topic, so they can't necessarily be expected to be a good judge. Also, sometimes better answers are posted later after the OP has stopped interacting with the question or no longer has the ability to test solutions.

The score of a post gives a more reliable indication of its quality, as potentially more (and possibly more knowledgeable) people are involved in determining it.

Therefore, I think we should have the accepted answer sort according to score, rather than being pinned to the top.

For anyone interested, [here's an SEDE query](https://data.stackexchange.com/askubuntu/query/1457743/questions-whose-accepted-answer-is-outscored-by-another-answer) for posts where the accepted answer is outscored by another answer (according to this, on Ask Ubuntu there are around 9000 such posts).