Why?

In baby logic we're taught to distinguish between explanations and arguments.

The classical method of making the distinction is:

Explanations show why something is true and arguments show that something is true.

Another difference is explanations deal with accepted facts and arguments deal with controversial issues.

The two paragraphs above form the essence of the difference between explanations and arguments.

My question is that from the standpoint of an inquirer there's no way to make the distinction.

Why?

Because both explanations and arguments must be requested through the exact same question, which is: WHY?

So, what are the benefits of this, what appears to be pointless, distinction explanation vs argument? If any?

Thanks.