I see the midgate as a huge bonus, for many things. I don't suspect it being a feature used daily, but when you want to haul something long, or if you want to camp in the bed and use the vehicle HVAC to keep warm of cool it could be nice. The only downside is that you lose the rear drop glass feature. I also like the folding back seats, as if you have big boxes they can go inside the cab.
As for comparisons to the Hummer, its really different, for most the Hummer is a vanity vehicle, making a statement, for me a truck is a tool. I only drive mine when I have to, would much prefer to drive my Tesla Y as a daily driver as its so much more sporty, and easy in town or parking lots. With the Hummer though, you miss out on the power off boarding capability, and even the Hummer SUV, does not have the same capabilities as the SilveradoE. The benefit to the Silverado is obvious, more range , more efficiency, more truck capability, quieter interior, more comfortable, and more modern looking interior, more sporty handling, etc... For me the Hummer is much less attractive, like I have said before, I am not really a "Hummer Guy", I was just interested because it was an EV pickup from GM primarily, but as the truck capabilities were released and fell to the wrong side of my expectations I became less interested.