Why are p-loops good?

I have limited knowledge about programming in Vex, but I just wanted to know, why are P loops/PID loops better than just having a button for set values of motor speed for the flywheel specifically. Our team wants to use wants to have a system to check using vision sensors, what the angular velocity of the ball should be, so I wanted to know if these loops would even help.

PID loops are honestly one of the coolest things I have used. The big difference is they will actively change the power being sent to the motors to get to the desired value as quickly as possible. The other benefit is than you know that (in this case) the flywheel is at the correct velocity. If you are just sending a certain amount of power to the flywheel, it is not going to constantly be at a velocity and not add or subtract power if it goes too fast or too slow. I am not entirely how it works with V5 because I graduated before V5 but I do know that PID control was pretty much essential in order to make sure flywheels were at the exact correct velocity. I think V5 has PID built it but I am really not sure how it works so I would check with someone else about that. But PID basically takes you to the next level of accuracy and speed and I would highly recommend checking out this guide to learn more about them: http://georgegillard.com/documents/2-introduction-to-pid-controllers

How does the PID loop regulate velocity? since the speed’s going to be decreasing once it is near it’s targeted value right? (Or is the targeted value constantly updated to regulate velocity like that)

You make the goal a velocity instead of a position.

Oh, Ok

Are PID loops nescessary to use with V5 motors, or does the motor itself handle them?

They were never necessary, they were just helpful. I will say the motors have a lot of bells and whistles and you won’t need to your own PID loop as often. There are definitely several places on an all V5 robot where one would be particularly helpful.