I'd heard the saying that "some airlines will prefer if you have done the MCC in a jet".
I know that some do like to see a JOC course (and will state this on their application requirements - Jet2 for example), but I've never physically seen the requirement to have done the MCC in a Jet. Except perhaps for the RYR MCC, which I dont think exists in the form it used to years ago.
I'd be interested to know who your thinking of AlexanderH?
Having done it, a handful of hours in a Jet sim will not make any difference to your employability as a Pilot. But it would probably improve your confidence during your first jet sim check........if you get one.