For me [based on my personal experience]MSFS helps me a lot to study deeply about the aircraft system and know the basic and advance fundamentals in flying,and other sort of thing will happened to the aircraft during flight or in the ground [failures and procedures..normal and non normal]i considered MSFS as my "training ground" to learn, familiarize and practice & procedures related in aircraft system...you can do anything in flightsim without risking of the following: 1.Life2. Multi-Million AircraftAs a "Real" Aircraft Mechanic..it's not only removal and installation of aircraft component or doing some wrench, torquing and do some safety wiring...it's very important to know how the system works, function that you're fixing/troubleshoot..flightsim and CBT are the good combination to learn deeply about aircraft system..why?CBT is also a simulated procedure to learn the aircraft system...but it is very limited and some CBT has only full discussion and some are combined discussion and click-able features....flightsim is more on virtual hands-on operation of the aircraft whether you fly it or not...simulations has a "limitation"CBT features all the info that you need about A/C but you can't fly or taxi the aircraft...flightsim.. you can operate the aircraft virtually but some certain features specially the FMC[boeing] MCDU[airbus] are very-limited unlike the CBT has...motoring the a/c using the MCDU/FMC or doing some BITE test... you can't do it in the flightsim but you can do in some CBTbut doing some functional and operational test...you can do in flightsim and see all the controls moving/functioning and set some failuresthat you cannot do in the CBT...we have a training called "Ground Engineer Initial Course" to learn how to operate the aircraft...and it will be performed on a Level D type simulator...starting the APU/engines of the aircraft...it's a very serious...why?anytime for these time when the turbine engines starts to run..what are this risk...1. FOD 2. FIRE3. Flame out/surgeand during run-up...it's a very risky part of the procedure specially if you're doing a high run-up checks....even the aircraft have chocks placed in the main landing gear..sometimes the aircraft will jump off in the chocks..because of high thrust produced from the engines....or some loose FOD ingested during run-up...many accidents happened already during run-upgood example is the etihad A340 jumped off in the blasting fence and the aircraft mechanic sucked into the 737 engines while checking the engines during run-upso again....it is really helpful to have these kind of programseither MSFS/ Level C/D simulator/CBTand i don't considered it as a "GAME" or Hobby...if you don't take seriously the aircraft......"Airplane usually kill you quickly---a woman takes her time"