When you need them, you NEED them.
I was handed a location recording recently where the band had walked on without a soundcheck, and the recorded levels were just too darn low. Bringing them up to a useable range raised the noise floor prohibitively, and it was impossible to "hide it" for a live acoustic jazz mix.
I thought I was sunk.
With a deadline looming, I tried the demo of the Master Restoration Suite. I'm usually pretty skeptical when somebody claims that a piece of software 'made' their mix, but I was speechless when I popped MR Noise on the 2-bus. The combined preamp hiss disappeared. No tweaking, no hundred-page tutorials, just . . . gone.
When I saw Sweetwater's sale price, I called up immediately.