Private Pilot training tends to be in aircraft but when training for expensive, hard-to-book aircraft which require special certifications to fly there's often sim training involved. Sim training is also useful if you're about to fly an aircraft that's similar but not the same as an aircraft you're familiar with.
Absolutely. Nowadays sims get more and more realistic and you can definitely learn a lot from them and transfer a big chunk of the learning to real drones.