Would agree with this. I noticed for some folks their enjoyment of the IEM mix is key. I personally just want to make sure it helps me play well.
In a big church where I occasionally play, mostly EG, their sound engineer was surprised I was planning to go mono because I had a stomp and a stereo Strymon reverb. Next time I was scheduled to play EG, I showed up with a stereo setup and told him. I asked how wide he was planning to pan it in the room and he told me it was just Stereo for the IEMs, that he always converted the signal to mono for the room