What's the use of theory and philosophy of education?

In the way the question is formulated, one begins to wonder: Why would it be relevant whether or not something is 'useful'? And 'useful' for whom, with regard to what? The choice of words seems to insinuate that, just like Achilles, we have to fatefully choose a way of action, as if one could do Theory and Philosophy of Education – or not, which would then demand a decision based on musings about the usefulness of both for something, or someone.