Now that I took a really good look at that design, does it matter in a shotgun how tall the bore is over the grip? Because that's pretty dang tall. Like a full lower, magazine tubes, and then the barrel.
In this context? No.
In shotguns as a general concept? Yes, but indirectly.
Side-by-side and over-under shotguns have historic "rules" for how things are laid out to achieve a theoretical ideal in handling, dating back to Joseph Manton. In theory, a double-trigger gun should have a straight, English-style stock, and a single-trigger gun should have a (traditional) pistol grip. Both achieve placing the hand as directly behind the trigger as possible - again, theoretically. Because of the stock designs, this means that the barrels have to be fairly close to the triggers. The barrels have to be in the right place for when the shooter puts the stock to his face and putting the stock to the face is supposed to be as instinctual and efficient a movement as possible.
Handling on a shotgun matters tons more on high end competition and hunting guns than tactical shotguns. How the stock and barrels jive is a big part of shotgun handling. Weight should also be minimized, meaning as little unnecessary space as possible. There was also much more practical concern back in the pre-metallic cartridge days of getting the barrels, lockwork, and trigger(s) all mated together as neatly as possible - the modern boxlock and sidelock are pretty efficient designs in terms of space, so by default, this isn't as much of a problem.
This isn't as straightforward as with pistols where people just assume high bore axis = poor design. Shotgun handling is much more subjective to the shooter. Shotguns come with stock measurements and people get shotguns fitted to them; with pistols, no actual modifications are made besides swapping grips and adding texturing.
There's also the issue of recoil and minimizing it by having the recoil energy go back as straight as possible, but in this context, the difference between pump versus semi-auto (and specific types of semi-auto) would make more of a difference than bore axis. Its a bullpup, the barrel, receiver, and buttstock are pretty much in line together.
Edit: TL DR, bore axis isn't a concern like it is on handguns, but its a factor in how a shotgun handles, which is important in contexts typically other than tactical shotguns, where priorities such as compactness, magazine capacity, and modularity matter more.