Someone should tell Q to halt all further development of the Erector 9, as it has been deemed stupid and pointless. Forget the fact that countless people have been asking for it since shortly after the release of the 22 Erector.

Baffles interrupt gas flow, not large depressions.

Ignorance of buyers is driving so many crappy designs these days

I think this is the 3-D printing tail wagging the style/marketing dog.  That process allows for surface features without extra set-up or tool change cost.  I question 3-D as the process of choice for this design since it would appear the mating threads and tapers are still conventionally lathe turned.  Brevis 3-D design seems well suited to the fabrication method.

Without seeing a Finite Element Analysis under both typical and proof loads it's hard to say if the (I suspect mostly cosmetic) lattice work just adds needless weight or girds the structure enough to allow the circular in-fill to be thinner.

It's pretty hard to beat the strength to material efficiency of uniform wall cylindrical pressure vessels. All you have to do is look at an aluminum beer can to see that form operating amazingly well.  Although the end caps shape and thickness is the design finesse in beer cans.

The numbers Sig quotes seem respectably mid-pack.  If this hits a decent price I think it will initially sell well.  The more joints or interfaces you have to manage it seems to me are either opportunities to mess up, or get left in one configuration that gets carboned into a semi-permanent state.  Long term users will determine the product  life.

Really silly looking guns are fashionable these days.  I can't tell you how many glock slides I've seen with all sorts of holes, cuts, and windows that aren't functional.  This is for people who have extra holes in their slides, flat triggers, and flat brimmed baseball hats.

While most people get the cuts because of appearance reducing slide mass does have a function.

3D printed surfaces are typically quite rough.  Threads need to be smooth or they will lock up permanently.  I'd bet those threads are 3D printed and then skim machined to give them the correct dimensions and surface smoothness.

I guess if you print indexing/alignment features then picking up a 3-D thread for final pass with a cutter isn't that big of a deal.