Couple of points, having done casting masters for commissions a time or two. Home printers aren’t great for masters (at least FDM ones, anyway); while they’re fine for end-use, you need something higher quality for a master or you’ll get every imperfection the print you’re moulding off has. You might get away without too much for terrain, but you’d struggle with models. You’d really want to get a high-quality commercial print done for that (and that can get expensive).
3D also prints don’t always translate well to casting without them being specifically designed for it, as they have different design criterion and you can print things you can’t cast. (And vice-versa, you can have finer details on a cast model than an FDM printer will print too.) The nomad, for instance, you simply couldn’t cast as a single piece because of stuff like the girders. E.g., when I did the masters for Kallistra’s WWI tanks, I did the CAD design in a different way to the way I do my own moderns/scifi, because of the different requirements. (Several pieces, different detail; the rivets on Mark IV my printer wouldn’t touch, but with the high-quality commerical master they used, they cast just fine.)