[bsder]

Because math is the tool while physics and engineering are the application.

So, now instead of one concept you have two unfamiliar concepts--one of which is far removed from your pedagogy.

It sucks, but there just aren't that many straightforward applications of abstract math classes.

[dr_dshiv]

The addition of a concrete example almost always makes the pure math easier to understand.

Knowing whether a particular aspect of math has real application is relevant to students. And this remains hard.