Well it depends on your realism sliders.
If they are maxed like mine then adjusting the prop controll in flight is important else the aircraft will over-stress and crash.
If your are at low then no, you don't have to use those, pitty is, it takes away the fun to fly sim for real IMO.
In reality the prop controll should be adjusted, so the fuel too. This ensure appropriate RPM and manifold presures in flight.
Having those in the red is like driving a car in 1st gear all the time. The engine will blow and then starts the twouble.
Each aircraft has appropriate requirements at climb, level flight and approaches when it comes to RPM and manifold preasures.

PS: It is similar to adjusting automixture controll, you may turn taht off in the sim, but if it is on, you have to mix appropriatly.