Jawgee, I cook the meat first, but not the veggies.
Shannon, the flour creates just enough crust to keep it from getting soupy on the bottom, which can definitely be a problem otherwise with all the veggies. Easier to serve and eat without it falling apart, too. It’s not really a crust so much as a baked edge, hard to explain… I think it gives it a bit lighter/puffier texture, too.