When food is already so scarce on earth in Interstellar, why did Cooper crush the crops while chasing that drone?
Was the drone really that valuable?
Now first of all, he himself says that its "solar cells could power an entire farm", so it is pretty useful in the first place. But what you also have to consider here, is that Cooper is actually an engineer and explorer and one of the very few people who have not lost their enthusiasm for scientific progress and who does not want to accomodate himself to this society of caretakers. This is also emphasized when seen in contrast to the teachers, who seem rather skeptical of Cooper's drone hunting endeavours. He knows about the value of the drone and that it is worth the crops he crushes because he is able to see the bigger picture and that it is not just about surviving today but also about improving ourselves to face tomorrow. Would Tom, Donald or those teachers have risked driving through the corn for such a supposedly useless technological relic? Probably not, but Cooper does!
And this is also exactly what purpose that drone scene and its consequences are supposed to serve. To show that Cooper is first and foremost an engineer and strives for progress tomorrow (and that the majority of his fellows don't actually share this attitude), even if that comes at the cost of crushing a few crops today.
Cooper's thought process is specifically described in the film's official novelisation.
The drone could not, of course, be bothered to follow roads, so neither could they. As fast as the truck would go, they were tearing through a cornfield, flattening the stalks beneath three tires and a wobbling rim.
He tried not to think about how much of the crop he was destroying, but at least it was his own field. He wouldn’t have an angry lynch mob showing up at the house in a few hours. And he knew it was justified. The corn was precious, yes, but you didn’t see one of these things every day.
Then he recognized the silhouette.
“Indian air force surveillance drone,” Cooper said. “Solar cells could power an entire farm.”