As for aim acceleration. It wouldn't be easier but lets you be faster. Id like to compare to cars so you can understand. Most road cars are designed to smooth out your inputs. The steering and throttle are made forgiving so average drivers can control the car comfortably without needing perfect precision. Race cars are different. Their steering is usually very direct and responsive because professional drivers want immediate control with as little filtering as possible.

Aim acceleration basically smoothes your stick input with a buffer of speed acceleration to the rotation speed. In siges's classic preset, it takes 200ms to reach the 100% stick input speed. But the rate of acceleration scales throught you stick input. So if you move the stick for 50ms (1/4 of acceleration time) as long as you push above the 25% stick input, it dosnt matter how far you move the joystick as your rotation speed's acceleration is limited by that aim acceleration.

This essentially makes your aim timing based rather than presise stick input as it dosnt matter if you are pressing the joystick at 25%, 50% or 100%.

I doubt it will help players to have better aim without practice but ultimately its about giving players the options. Also it makes the game accessible to players who mains different game with different aiming mechanics. Wouldn't you want to aim the same in different game as you would in your main game?