Like dummy tracks in Ableton and the way you can manipulate Mainstage on mac, Multi-instrument presets are a great way to save lots of CPU-power in a live performance, especially when you can call them as patch change on the show page. So I'm making multi instruments of both single and stacked instruments from different vendors. I can use this method when it's not an issue that it takes time to change the sound between songs.
Now, here is the problem I ran into. When calling a patch to fetch the preset of the multi-instrument, the individual inserts, sends and fader settings disappear from the preset. At first, I figured it was a bug, but it might be a feature that is needed since I can not get a workaround other than setting up another multi-instrument on that row/player. If you like I run 30 to 50 different songs on a gig using several keyboards and pads it will be a big load on the computer with all the multis opened. Both on mac and pc, I run both.
You need a good CPU-headroom to keep yourself out of trouble doing live shows.