Recently a friend and I were chatting about how irrelevant our education has been as far as the work we do for a living. When you consider the cost of acquiring the degrees we need to enter the job market, you have to wonder if the time and effort (and in many cases also a great deal of money) would not have been better spent learning vocational skills that we could have found some practical use of. For a lot of people, after a number of years in the workforce, their academic degree becomes more ornamental than functional.
Of course there is education that is worth acquiring simply because we want to broaden our horizons or have a passion for a certain subject and want to immerse ourselves in it. With those goals, it may be entirely acceptable to not find any "material" application of the learning - as would most likely be the case with some of the stranger courses offered by American universities.
The worst casualty of not being able to use or apply your education in the workplace is probably the stagnation of your mental faculties. At some point ,your paycheck becomes dependent on your speed and proficiency at a certain set of skills that rarely challenge you to apply knowledge in unusual ways let alone require you to learn more. It does not surprise me that the concept of a "brain-gym" is catching on - clearly a lot of people are not getting the mental exercise they need from the work they do for a living.