You could get similar resolution by stitching together a few hundred frames from a DSLR. I can't say I've ever produced a 3.2 gigapixel image before, but I have exceeded 500 megapixels on occasion.
Stitching has its limitations, but it doesn't require a medium-sized truck and a crane to carry and set up your gear. That's an important advantage for me, since I much prefer to drive a smaller vehicle. My wife also appreciates the lower cost.