Well, if this doesn’t tread on aircrew sensibilities ...
... ATC training moved heavily into Simulator Training decades ago, including the Visual (VCR) simulator at Shawbury. Numerous reasons, but for training purposes one has a controlled (no pun intended) environment ... irrespective of real-world weather, traffic density etc. Whilst I completely accept it’s a different environment from flying, how many real-time flying sorties are aborted for weather, serviceability, lack of other participating assets? I know from personal experience how much ATC training/continuation time got wasted due to lack of, or too much, traffic for the trainee’s experience/skill levels.
Where the real/simulated dividing line lies is way beyond my pay-scale/experience.