I've heard claims that engaging in activities that are neither interesting nor important has intrinsic value -- it helps build character, makes one grow as a person, or it just might turn out to be important.

If it builds character, makes you grow, or turns out to be important, then it is important, its importance is just surprising.

What people might actually be doing is operating with the knowledge that they are not good at distinguishing important information from unimportant information. Thus, it seems safer to try to learn as much as possible, in the hopes that that will include the important things.