There is a lot to be said for having the Quality Control and efficiencies of a manufacturing facility behind your home construction!
The number of decisions made at the level of the guy swinging the hammer in normal on-site construction is pretty high. Some of these guys are experienced and make good calls and others just make sure it looks good enough to not draw attention.
In a good manufacturing facility, the flow of materials and quality checkpoints prevents the individual craftsman from being confronted with having to "improvise".
I have a friend who worked in one of these facilities and later became a contractor. He said he would choose a modular pre-manufactured home (not sure I am using the right terms) like you did for his own home if he ever decided to stop flipping homes.