[exmadscientist]

I mean, we're talking about making the napkin sketch that you hand to the real draftsman. The format really doesn't matter; they want a PDF (or whatever). They are not going to open your HTML/CSS/JS tool even if it would be trivial to them. They have better things to do with their lives. So what tool you choose is up to you and should be whatever is best for you. It doesn't matter what the shop is using.

Proper constraint-based drafting is indeed quite hard! But I think the whole "lay out this 2D grid-like structure with a few rectangles" problem is probably one of the first things anyone would learn to do with it, and I'd submit that it is indeed probably about a couple of hours' work, for someone already reasonably technical. The moment there's more than a single sketch involved, or complex geometry in that single sketch, I agree with you that it's asking too much.

The real benefit is that you are starting to learn something new. CSS is not going to help you (insane contortions aside? I really don't want to find out) when things like circles appear. And yet, if you know how to do 2D sketches, you can find yourself using them to solve other problems, just because you already know how to do it. And that's pretty cool! (For example, I've had living rooms that were just awful to lay out. It was a real nightmare to figure out how to get a TV into that place. So I sketched it up and messed around until I got something viable. My original plan was just to print out some pieces of paper to scale, then mess around with those, but it was soon clear I could do it all onscreen, so I did.)