It is a tick box to have, I am now employed in a TP and all that was needed for that was the certificate, where and on what it was done was never discussed.
I see what people say about getting some experience on a jet first though, although most of my MCC was flown on autopilot, a sim assessment will not be, and nor will all of a type rating, of far more use for both of those will be ensuring that your scan is up to speed to be honest, well from my experience anyway. The MCC does introduce you to profiles though and learning settings, checklist management and calls etc.
If money is no object do it on a jet, if it is tight then do it at the cheapest place and spend any spare on a couple of hours in a jet sim nearer the time of a type rating or sim assessment. And keep your scan up!