In my opinion, the sim is basically a more user-friendly version of what some prog statics already do.

When some groups reach a new mechanic, they review the mechanic, draw up a plan, then they queue into T4 and the raid caller opens a recording of the mechanic and calls out what's happening when while marking people and those people will move according to the plan.

The sim automates the mechanics so the calling according to a recording of the mechanic doesn't need to be done. In essence, it's a more pug-friendly version of queueing into T4 to plan as it doesn't require voice chat or a video recording of the mechanic.

The sim does have the advantage of having accurate mechanic timers and AoE sizes. But is it really cheating? I'd say it's probably about as much a cheat as pre-planning in T4 with a raid caller on voice chat is. In essence, both ways is your team preparing for the mechanic before queueing into the fight, the sim just has the advantage of being game-accurate.