The distinction between while and though is neglected but should be recovered. The writer observes it is clearer and more useful to his reader. Most often today, even in edited publications (e.g., newspapers, magazines, and books) one sees them used interchangeably and typically as if both only signal a concessive clause. This is incorrect not because English does not change but because some changes signal a decline rather than an improvement.
As is often the case the solution here begins with definitions. While now, as it has since the 10th century, has reference to the passage of time. Even the Scarecrow, who wanted a brain, knew that.
Scarecrow would “while away the hours” because he knew that the verb “to while” meant to pass the time. If we remember that the noun while means “as time passes” and the verb means “to spend time” then we can see a clear difference between while and though. If you mean to signal the passage of time, use while:
While Joey Bagadonuts stood look out, Louie ransacked the Bodega looking for Doritos.
Joey is doing one job and Louie another but they are doing them simultaneously.
By contrast, though signals a concessive clause, which is a way of communicating to the reader that one thing is happening despite the fact that something else is also true. In this case time is not in view. It is often used with the qualifier even:
Even though Louie was not a very good at it, Joey Bagodonuts always made him drive.
Though signals that despite the fact that one thing is true of Louie, namely, he is a poor driver, another thing is also true, i.e., Joey wants to conduct the burglary himself. Though concedes one thing and asserts another.
Writers often confuse while for though by using while to signal a concessive. This is unnecessary. When you mean to signal the passage of time, use while. When you mean to express a concessive or perhaps a contrast, use though.
Though virtually no one observes the distinction, while I have anything to say about it, I will continue to encourage writers to distinguish the two.