This isn't a question with a single answer, as it really comes down to what you value as an individual.

Having done world prog basically every tier since Final Coil, I'm more the opposite. I live for the adrenaline of finally conquering that one hard mechanic deep into the fight through high consistency at getting to your prog point as a team. Getting past Intermission 2 in A8s on week 3 of Midas only to see brute justice unfold his wings is still one of my favorite moments in my raiding career. Or finally conquering wormhole just to see Perfect Alexander's megazord sequence within a few pulls.

Using the simulator would ruin that experience for me. It's easy to conquer any mechanic regardless of difficulty when you can ram at it for 30x an hour due to starting right at it again. Which is also precisely part of the design behind encounters - you could technically de-incentivize the simulator by putting every hard mechanic right at the start of the fight, but it results in a very boring fight once you get past the initial zerg rush. They spread mechanics out, sometimes deep into the fight, to increase the time people spend progging fights, and to attempt to create a more smoother difficulty curve through the fight overall.

That being said, people are free to do whatever they want. It's become more popular lately since at the end of the day, the majority are motivated by rewards, and have little qualms using stuff that helps them achieve those rewards quicker. Like I mentioned at the start, it really comes down to what people value.