USB/Serial chips are all very small, and we had trouble soldering them by hand.
FTDI chips are $4.50, plus the other parts that go with it. Pricewise the module works out to about the same, and it only has regular 0.1" pins to solder.
The module can be left off, and an offboard USB/Serial adapter plugged onto pins for programming and then unplugged when USB connectivity is not needed for embedded operation. I was going for a modular board that could be user repaired.
That makes it as easy as the Uno. I can't make is as cheap when I'm only working in qtys of 25 that I slowly sell, vs Arduino making thousands and selling worldwide. $22 for a kit of parts is pretty darn reasonable, and $10 more if you want built in USB.