When building a smoker, you have the option of buying sheets of steel and cutting all the pieces yourself or having a shop cut all the pieces so you only have to assemble it. Obviously, cutting yourself is more time consuming and time needs to be spent cleaning up the edges and adjusting for mis-cuts. Having it laser/waterjet cut makes a cleaner and more exact cut.
So, to answer your question, the CNC file has all the pieces nested in a sheet and all the cutter has to do is plug it it to his machine. Without it, they have to type in each piece separately which usually increases the operator cost and produces more waste.
Personally, I think it’s much more fun and rewarding to cut everything myself but will admit it took a ton of time to do so. I nested all the pieces from the regular plans on a sheet of paper before I started and was able to make very efficient use of my material and minimize number of cuts. If you complain enough during the build tho, maybe the Mrs will give you permission to buy a plasma cutter and a bandsaw for the next project......?
Personally, I think it’s much more fun and rewarding to cut everything myself
Unless you are like DT and enjoy the hard slog of cutting everying manually (measure twice, cut three times), I would definitely go with the cnc dxf files. A few bob more, but man it does save heaps of aggravation. Not to mention cutting disks, grinding disks etc.
I am in the fortunate position of owning my own cnc plasma cutter so I always got the dxf files if available. So I might be a tad biased.
Learning generally boils down to "Repetition or the avoidance of pain", some people learn by doing, some by watching and some just have to pee on the electric fence.
Whether you think that you can, or that you can't, you are usually right. Henry Ford
I'm from Delaware. I cut everything myself for my mini GF build except for the firebox plates. I had my local steel dealer cut that for me. What are you going to build?
I bought the CNc plans, but most of the metal shops just didn't seem to know what to do with the cut file. May be worth asking your metal guy if it would be of any use