Where it is used
Real sites, and what was stuck before.
One wrong digit in a parameter, and the machine crashes
On-site elevator parameter changes rely on the manual plus experience, then get pushed straight to the board.
One misplaced decimal point and the car overshoots the top or bottom, taking the elevator out of service for a day at best, damaging parts at worst.
Run the same parameters on the virtual elevator first and watch how it moves. If the rehearsal fails, you can't proceed — only once it passes are you allowed to write to the real machine, and the original values are backed up automatically before the write.
New hires have to wait for a real elevator
Training new hires means waiting for a free elevator on site, and only one person can stand at the control cabinet at a time.
Real elevators can't be scheduled freely, so new hires get little practice time — and a real mistake means taking the elevator out of service to fix it.
One computer per person, each a virtual elevator — try anything, inject any fault, and get comfortable before touching the real machine. The free edition already does this, no license needed.