There are so many reasons why I, as an engineer, will never even attempt to use AI for mechanical design, that trying to list them all is about to give me an autistic screeching fit.
Even if all I need is a simple little bracket or something, I can model that and know it's right much quicker than I can ask the AI to do it and then check it's work. There is no time savings here.
Heck, for any of the stuff I need that is simple enough to plausibly ask AI to draw, I don't even bother to model in the first place, I would either sketch it with a pencil or just make the piece right off the top of my head.
If it's more complicated than that, then my approach grows to include things like what stock I have available, what tooling, fixturing and machines are present, whether I can use any COTS hardware to simplify the design, the tolerancing scheme I want to use...and my output needs to include not just the model, but toleranced drawings and any other assemblies and such that are required.
And besides all of that, and with love....OpenSCAD is a joke, and if you seriously try to tell me that "the best paradigm for CAD generation is to generate CAD as code", I cannot take you seriously.