I'm a PPL and a Flight Simmer and get great pleasure from both but don't really relate the two directly. Flight Sim can be many different things to many people and I wouldn't class it as an arcade game by any means. Buy one of the commercial add ons - Embraer 190, B737 etc and you have to use some pretty detailed procedures to derive the full experience of "flying them". If you have a reasonable PC with good graphics it can be alot of fun flying "commercial" aircraft from A to B under ATC control while downloading real time weather etc.
AS a PPL - I have found it useful doing approaches to various "new" airfields which are normally pretty detailed in FSX and realistic in terms of taxi ways, runways and terrain.
It's also an excellent tool for instrument practise and preparing for IMC etc.