Personal opinion: If you mix OTB, it's counterproductive to rely solely on DAW automation. I can only speak to early versions of C_base (SX-3) and current iterations of ProTools, but their mix automation is essentially clunky and annoying compared to the DM's. The advantage, though, is having both available for specific things.
Why 'clunky and annoying?' Simple: if signal is summed to the DM and mixed down from there - either back to DAW or another target device - any fader changes in the DAW will most likely screw up compression, efx, and gain staging carefully set on the DM's OTB side.
Think about it: you perform a fader adjustment ITB while monitoring the signal OTB. Whoops! Why did that bass track suddenly sound 'fluffy?' Because you didn't bring the DAW's fader back to its absolute original setting; now it's clipping the output to your mixer!!! And - DOUBLE WOOPS! Seems you forgot to reset track 27's Automation button back to 'Latch!.' Sorry 'bout that! Your xylophone track's fader just slammed down, and because you didn't have your Remote Layer screen up, you didn't notice.
Now - you've gotta go back and overwrite the messed up maneuver.
So - in my narrow view - if you're an ITB kinda guy - better you auto/mix ITB as well. But if you're using the DM its fullest potential - OTB - you're shooting yourself in the foot not automixing on the DM. However, there's no law that says you can't use both tools; I prefer to create cymbal crescendos using the DAW's faders, leaving the DM's faders for fine tuning. This is one case where two wrenches beat a pair of pliers and a tweezer.
My opinion; you may disagree to your heart's content. That's what makes the world go round.
CaptDan