To carry the sports analogy a bit further, the advantage may be considerable if the employee's job responsibilities include sales, negotiation, or public relations. In those situations, a tired employee may cost a company a sale, an important term in a contract that could be worth millions of dollars, or a bad impression that might damage a company's brand image. Like an athlete, many of these folks are expected to perform at their best at a specific time, perhaps within hours of clearing the airport. All of those considerations could make an economic case for business class over coach.

Having said that I'm sure in the last decade, this argument was applied to a much larger class of folks than originally intended and became more of a perk than a justified business expense.