I don't think this kind of AI will be that useful for CAD, the time consuming part of CADing is the precise details of things that need to fit together and often iterated on because of various mechanical, electrical and material properties.
A lot of CAD work today is based on parametric design, constraint solvers and letting you CAD software solve various optimisation problems. One of the big problems with this is that the dimensionality and search space involved can be huge. Using AI to narrow the search space that these solvers have to deal with will be a significant and obvious win, and work is already happening in this space.
Combine that with an AI that can generate an initial design based on a rough specification, have the user apply some constraints and then iteratively have the AI generate new designs, based on known good designs, that fulfil those constraints could be very powerful.
