IMO there's another good reason to use the class D power section.
This is likely to be an unpopular opinion around this part of the forums, and I'm probably not a very good representative of the primary target audience of the Darkglass products, but I often feel like I get the sound I'm looking for better from modern class D amps (Genz Benz, GK MB800, etc.) than traditional tube amps. Honestly, I think Ampeg SVTs and Markbass amps sound great, and I use them from time to time, but while it's the perfect sound for classic rock, it's not the sound I'm looking for. I'm looking for really harsh, bright, clear, articulate and slightly brittle tones, and I don't really appreciate the tube sag or tube compression or tube warmth as much as getting a brutal sledgehammer tone. To be honest, I would rather run my B7K into a mixer rather than into an SVT, which seems to take some of the edge off my tone.
So when I heard rumours of a Darkglass amp coming up, I was really hoping that it WOULDN'T be a tube power section or one of those heavy rail sections. Having it run into an ICE module fits my needs perfectly (I was considering upgrading to the GK MB800 for some time, but hesitating because I don't really need to spent money at the moment, and then when the rumours came up I decided to just wait and see).
Maybe my ears are just immature at the moment and I'll come to love tube power sections eventually, but for now it's just not me.