A simulator is just that --- a SIMULATOR. It is NOT a teacher.
A sim will allow you to fly an R/C airplane without the fear of crashing that airplane. It will allow you to “feel” what movements of the sticks on the controller will do to a plane in flight. It will help to “train” your fingers to do what is necessary to properly control the flight of an R/C aircraft undo a great many different conditions and situations. It is a great learning tool that properly used, can help tremendously with your learning progression.
I hadn’t flown for more then twenty years. And prior to those twenty years my total experience consisted of less then half a dozen flights all with an instructor standing beside me. After several hours on a sim I soloed after just one buddy-box flight. But, I practiced using a syllabus from a club I found on-line. Starting with large circles, to rectangular patterns, to figure eights, all while maintaining altitude … eventually advancing to landings. By the time I flew that buddy-box flight I’d already advanced, on the simulator, to an intermediate pilot.
All of that said, there is no substitute for flying in real life. For me, nerves are a huge issue. I can do torque rolls, hover, do harriers all day on the sim. I can fly the smoothest pattern routines ever … at the field I look like a beginner practicing landings, and not doing a good job. And that’s after about 6 months of flying the real thing!