Not a professional CAD user myself, but as a hobbyist with an interest in this space I've never heard of the former case, so I'm curious.
This one, I should had frame it better.
> I've never heard of the former case
I don't think the CAD software itself is a point of a regulations, but there are definitely some standards and regs regarding how it should be done. A quick search yielded [0] which is a nice example of how it could be done by a hand, yet it would help immensely if the CAD software would aid and do the things by itself, saving both the time and man-hours.
[0] https://www.gsa.gov/real-estate/design-and-construction/comp...
I do wonder who is liable if the software used to design a bridge outputs incorrect simulation results and the bridge collapses as a consequence. I suppose it's on the senior project engineer (or whoever ultimately signs off on the design) to verify the results somehow.
Edit: This article [0] talks about "trust" being placed in commercial CAD software by engineers and doesn't mention regulation/certification of the software itself, which seems to imply that there is none.
The biggest trouble (after making a CAD software itself) is to keep it in line with a current regulations. I'm not familiar if A. even does that, but some regional alternatives are making money not only on the SW itself, but by providing services related to be in the compliance of regulations.