They're mostly not. Guntubers have given a lot of people that didn't grow up with/around firearms basic knowledge and safety info. It's a pretty sweet deal.
Most of it is focused on corporate shit. Integration with ERP packages and full manufacturing data. They also host a lot of plugins that sometimes work out mostly okay lol. NX has python scripting which I'm a fan of at work, but I mostly use models at work so I'm just using it to get access to a python interpreter.
If you look up the release group solidworks (if they're still around, ru cad focused) they release a lot of random modules for the different CAD packages.
In most commercial software you can create a sketch, draw a shape, extrude it out, cut some holes in it and it stores it in an ordered tree. You can go back and change the first sketch and it'll go back through and update the resulting model. If you export that as an open format you only get the result of all those steps - you lose the instructions the software uses to create them.
You can do other things like have parameters. You could make a sketch and have dimensions defined by a statement dim2 = dim1 * 5 sort of thing. When you update dim1, it would also update dim2.
I don't know where OpenSCAD fits in here. I should play with it a bit. I suspect scripts can be written to behave very similarly.
There's also a lot of other shit crammed into commercial formats - materials, drawings, stress analysis and other shit we wouldn't normally need.