In the 21st century, the economy has become so complex and so dependent on knowledge that education for all people is more important than ever. 50 years ago (and even more recently) there were plenty of good jobs for people who did not have a great education. Today, that is much less true. More and more jobs in advanced economies like that of the US depend on people having strong academic and intellectual skills.
For this reason, it is important to understand the exceptionalities of all students. This is because it is easier to give the students a good education if we understand them individually. It is more important than ever to tailor our ways of teaching so that they will match up as well as possible with the individual needs of the students. If we teach students in the ways that are most appropriate for them, we are more likely to create a situation in which all students are well-educated.
Because our modern economic system makes it necessary for more people to have good educations, it is important to understand how various students are different from one another so we can give them individualized educations.