@Linkat,
You are the exception rather than the rule, Linkat.
This is the equation behind the math you are talking about (to determine the difference between paying points and getting a lower interest rate). Good for you that you can do this math to solve for 'n' or for 't'. Most people reading this couldn't solve this equation for 'n' or for 't'. Fortunately they don't have to.
The point is that you don't need to understand exponential functions to make this calculation. The calculation has already been done for you, you just plug in the numbers... now with the internet you don't even need that. You just take someone else's understanding and plug in the numbers and ... viola. Someone in the sixth grade can do this too.
I work in engineering, and I am a math geek. When I recently financed a car, I didn't even do the math. I know that fewer months means less money over all. I understand that lower APR means less money over all. I knew the monthly payment over all I could afford. I used a calculator to come up with the monthly payment. I didn't even have to think about exponential functions to make this decision.
I could solve this equation, I work regularly with exponential functions in my jog. But I didn't because I didn't have to.
That is my point. You can live a perfectly fulfilling, successful and productive life without knowing how to solve exponential functions. In fact, most of us forget this stuff soon after we learn it.
The truth is, even for dealing with interest payments, you don't need it.