I use pipe and wire when i work. I would be lost trying to wire a house/business with NM cable. The reason for pipe in commercial work is to allow for flexibility down the road. As for residential, it offers the same.
If additional circuits need to be installed, the raceway is already in place. Yes, it does raise the cost of the install but in my opinion, the additional cost is worth it. Pipe does offer better protection of the conductors compared to NM.
Now i know some will say that if the NM is installed properly there is little risk of damage from drywall screws, etc. WHEN it is installed properly. Also, if there is a problem down the road, get out the saw and start opening walls.
I'm sure all of us could go round and round with the merits/faults of each wiring method. Some will say the only reason to install pipe is to increase the hours on a job. Others will say anybody with a pair of strippers can install NM. To each his/her own....
