You wear khaki and golf shirts and want to know what use a tie is? ( BTW if you are going to use words like raiment at least spell them correctly).
What use is khaki and golf shirts in an air conditioned office or car. If you work in a hot humid city the best dress is nothing but a speedo. Are you really saying people should wear speedo's to work?
You argue against style and then proceed to use style to determine what you wear.
Yep, misspelled raiment. But style over substance is still silly. That is to say, a tie serves no purpose other than adding color to a drab outfit.
I view clothing as gear/equipment. Your mileage may vary.
Cheers