>If I haven't created it myself and yet still have an end product, how have I accomplished anything?

Maybe what you wanted to accomplish wasn't the dimensioning of lumber?

Achievements you can make by using CNC:

    - Learning feeds+speeds
    - Learning your CNC tooling.
    - Learning CAD+CAM.
    - Design of the result.
    - Maybe you are making tens of something.  Am I really achieving that much by making ~100 24"x4" pieces of plywood?
    - Maybe you want to design something that many people can manufacture.

The CnC machine is aiding in teach, it's not doing it for you. It's being used a tool to increase your efficiency, learning. If you were asking the CnC machine what is the best frequency and to set the speed of the spindle you're still putting in your own work. Your learning the skills of the machine via another method and no different as if you worked with a master carpenter were asking questions.

An electric wheel for clay making is going to result in an quicker process in making a bowl than using a foot spindle. You've still need to put the effort in to get the results you want to achieve but it shows in time.

Using LLMs for let me do this for you is where it gets out of hand and you've not really accomplished anything other an elementary "I made this".