Has nothing to do with max. It's all to do with efficiency and effectiveness. 2000rpms is already generally fast enough.
Well when you mention "threshold", that leads me to believe there is a certain speed it has to reach, correct? You never mentioned where this threshold is, or anything else.
So basically what you're saying is that fans degrade overtime. Excellent argument
As I said earlier, fans cost barely anything to replace compared to a HDD, CPU or logic board. Running my fans at half capacity isn't going to rip past some mystery threshold and ruin my fans.
Before I started using this program, my cpu was about 20 C hotter all day than it is right now. What could possibly be harmful about reducing that? Cooler components = better components