Is your room really that noisy?

pumping room/ambient mics off of close mics
opening a 2nd mic strictly when the first one is keyed (front of kick, bottom of snare)
opening a more distant mic when the vocals hit a louder db (david bowie heroes)
making a guitar line pump up a few dbs on the kick drums (sex pistols nevermind the bollocks)
master drum buss jump a few dbs for transients etc

sure you can 'draw' or slice all this stuff in a daw, but its time consuming and time is money.

Curious which functions are missing. Thanks

I don't see a Range, Hold, Knee, or Ratio parameter on the Waves C1 and associated versions. I don't think the left hand side with the Compressor settings has any effect on the Expander side (right).

Yikes. Half assed dynamics software with most of the kit missing.

Gated/expanded reverb on snare drums can get you that huge 80's drumsound

I also use an expander before and after a send to external outs
going into noisy guitar pedals that i use to get gritty sounds.
Distortion pedals tend to push the noise floor quite a bit,
especially with extreme settings.

The expander after the pedalboard out reduces the noisefloor, buzz and hum when not actually playing notes through the pedals

The expander before the pedalboard input does this too, but it has the added advantage of making rythmical sounds tighter by the reducing & cutting of reverb tails and fadeout/releases. Distortion pedals tend to smear these into one drawn out mess, and this way the notes are more punchy and pronounced.

i'm using the fabfilter one, don't forget to eq the sidechain to make the response more musical and precise

I've used expansion to shape bass guitar attack/sustain, but being level dependent, track variations in that roll make it hit and miss.
Transient designer plugs do about the same, and much easier.