Most shops print 1-2 color jobs 80% of the time so in my opinion a triloc isn't even worth the time it takes to swap out the pallet for easy 1-2 color jobs. If you expose two images on each end of the screen for jobs then you'd have to load the screen twice in a cts for it to reliably register with a triloc on press.
I have to say complete disagreement, mind you I built my own FPU and on-press regi jig. The FPU doesn't require carrier sheets and the on-press jig fit on a platen so we don't have to remove one. We use it even when setting up a 1 color black print on whites as it's just plain faster than doing it by eye.