This is really bad advice to be giving out. Yes there are the rare people who can spend time on a sim and then successfully fly a real plane, but people like that are rare. In fact, those types of people are natural pilots and usually need little to no training to fly. And they are usually 1 in a 1,000. The other 999 of us out there really need some sort of training, even after they have plenty of time on a simulator. I have countless hours on MS Flight Simulator and can pilot a jetliner from one coast to the other, would you fly on a 747 that I'm at the sticks of? Of course not. You have to realize that simulators are a training aid and not designed to be a primary training device. I have watched lots of pilots spend time on a simulator without any formal instructions, and I have watched these people develop bad habits because of this.

Here's a list of some of the "bad" habits one can develop:
1) Failing to keep the plane straight during takeoff run.
2) Climbing out too steep.
3) Not maintaining a constant altitude while turning.
4) Turns that aren't smooth, too sharp, etc.
5) Forgetting that there is a left stick.
6) Not lining up with the runway during landing approach.
7) Using ailerons instead of rudder to make course corrections when landing.
8) Using the elevator to extend the landing when you realize you're short.
9) Failure to learn the signs that a plane is about to stall, and what to do to avoid it, or recover from it.

A simulator is a great tool if used in conjunction with an instructor, and can greatly reduce the training time it takes to learn to fly if used this way. But it's not designed to REPLACE an instructor.

That's my 2¢ worth

Ken