I love business! i value what i learn from the class, it's something you can used in the future( what you've learned) especially when you decide to have a business on your own.
I agree with #4; the most important thing you can learn is effective leadership and management of people. As a three and a half year veteran of a job with the worst management in my experience, I know how even a reasonably good job can become impossible because of bad management. Once you understand how to treat your employees, everyone's job becomes better.
I think what I learnt most from the various business modules I did as part of my study is the importance of change and how every organisation has to be open to it and seek to make it as easy as possible. This is of course difficult if the change is a big one or you have employees who find embracing change difficult.
To say that businesses run the world around us is a truism. Most decision in the world are made based on finances. For this reason, a class in business management will help in understanding the world. Also because business is so embedded in our world, many principles of business are transferrable.
Some managment classes teach skills essential to effective leadership within an organization. Having a class that teaches about issues related to motivation, assessment/evaluation, hierarchy of leadership, and topics like that could important to you no matter what kind of business you work for or where you are in the grand scheme of employees.
The most valuable thing I learned from the management classes I took in college is that every detail matters. In business, it is easy to get caught up in the bigger picture and forget something else. That's why you need to learn to delegate, so that nothing gets lost.
A business management class can also be useful even if you do not start a business. It helps you to understand how businesses work, which can be useful even for people who are customers or who are just interested in knowing the way the world works.