Absolutely. It's something cognitive. The mind is more creative when there's blanks to fill in.

I played around a bit to see if I could style HTML+CSS to look sketch / toon / hand drawn. Precisely what I thought Balsamiq was doing. Wouldn't that be awesome?

Alas, I didn't get very far. I chopped a hand drawn box into 9 GIFs (upper left, upper middle, upper right, ... lower right) and attached them to a DIV. A lot of work. And the long edges could only be stretched, vs repeated. And I couldn't fathom a way to "owner draw" (old Win32 dev here, sorry) other widgets like dropdowns and scrollbars.

If there was a way to access each widget's vectors, then a hand drawn style is totally feasible.

Perhaps once zoomable UIs become common place.

svg might help you there, inkscape has a jitter filter. It creates more vector nodes, but it would display on a webpage and is open format like html