For example, some people read a boring book and think it's a waste of time, while others can read Yan Ruyu and The Golden House.
Are the bricks on the ground useful? What's the use of water in the swimming pool?
Whether it is effective or not really depends on how you use it.
It's really useless if you waste your time in college.
The problem is that even though you know it's a waste of your money and time, you still think it's useless. Ask yourself, is college really useless to you?
As you said yourself, universities basically rely on self-study (self-examination). How much have you taught yourself?
You are not in college, can you learn this? You can consciously stop wasting time and money? Not necessarily!
In that case, don't complain here. Whether you are in college or not, don't waste time. Make yourself useful instead of complaining that your college is useless.