Why we learn math (or anything for that matter).
As babies, if we never learned to walk, could we still survive in this world? I think so. In fact, it is much easier to keep your balance on four legs rather than two. It is hard to learn to walk, with all the falling down, the trial and error, and mostly error at the beginning, all the bumps and bruises, the tears. Why do we even bother to teach our children to walk? Well, walking does make life a lot easier, and maybe in the long run it's worth it. For instance, it is much faster to get around on two feet, rather than crawling. When getting around in the street, all of our clothes and hands don't get dirty, only the soles of our shoes do (again a convenience created for "walking people"). Also, it is much easier to carry something while walking rather than crawling (multi-tasking).
If I didn't know how front crawl, I would have to doggie paddle to get to the other side of the river. If I didn't know how to drive, I would have to take the bus everywhere or walk. If I didn't know how to use pythagoras, I would most likely have to draw a scale diagram for any sort of construction or wood working project, and estimate the numbers. If we don't know (advance) math, obviously we won't use it. However, if it's in our blood, our second language, we will find places to use it at every corner, everyday, even in our sleep. Math is a way to organize the world around us, and with more advance tools (such as exponents, logarithms, trigonometry), we can organize more and more.
Teaching advance math is like teaching a baby to walk. Of course, it is not absolutely necessary, and we could get around with only arithmetic (and many people do this). As teachers, however, we should realize that the world is desigend for people who know advanced math, and instead of crawling, with the skills of math our students can get up on two feet and run. Whether your student is pursuing a masters in human resources or becoming an accountant, it is important that they learn as much as they can.