You are aware that by accepting an answer you gain 2 rep and the person you've accepted the answer from gains 15 reputation? This would be one of the reason it is recommend to accept the answer that solved your problem irrelevant of the votes.
Vorting does indicate the more correct answer, however in some scenarios the highest rated answer is not necessarily solving the particular problem you may have. Also when someone hits the site from Google that does not know about the voting, the first things they will look for is the green accepted answer tick. This is unfortunately from the site that shall not be named era of finding answers.
With regards to the update
The feature was requested by the community here on MSO. The reason for this is that people take a lot of time to write complete and good answers, hoping that theirs is the one that will be accepted as correct. Also the goal of SO is to be a repository of correctly answers questions that people can search and always find the latest information or solve a specific problem. Therefore the acceptance rate has been made visible to give users another reason to accept answers.