I used to be heavely involved with MSFS addon companies and did a lot of work with flightdynamics guru Rob Young of RealAir Simulations.
Firstly MSFS with the correct addons is a very useful tool. I totally disagree with other posters above.
Watch aerobatic pilots simulating their manouvres using the most basic simulator of all "their Hands" and you may realise that getting things clear in your head rather than in an expensive aeroplane will save you a lot.
Sitting at home sorting out NDB flying saved me a fortune.
Some of the photo scenery and weather depiction is so real that fly the sim route and then the real route and you will know exactly where you are as you will have been there before.
I always used to feel that the sim was most realistic on autopilot and for instrument flying.
The biggest problem was the flight dynamics and puppet on a string handling.
Rob young went a long way to try and improve the flight dynamics although the flight dynamics engine in MSFS was complicated and flawed.
It was a matter of compromise. We got a half decent spin out of the sim but it was frustrating to see one area improve for another to decline.
Used properly it is an excellent tool to keep you currrent when you are not flying as long as you appreciate its limitations.
Pace