On the one hand (++), you give the reader a warning, "It's a simple function for the sake of our example, but let's imagine that it's complex and would be costly to rewrite." Good; 'cuz it leads to the inference that your basics will be more easily absorbed using a "simple" example.

To head off critiques such as some already offered here, though, you might want to offer a much more complex function as an example of why currying is desireable -- perhaps even before the existing one.

For example, you may have a specialized function like this: ((sorry way too new to write that)). Now, suppose new management wants you to write a package that does essentially the same thing, but with only a few possible inputs. But rather than do it with a complex example (that will make it harder to focus on currying), let's pretent the original function is:....

Re the writing: splendidly clear and concise. This noob had difficulty only with one phrase... and that was simple lack of background... most of which you subsequently supplied. Well done!

Will be watching the tread.