Personally, I wouldn't spend time setting smooth scrolling up, not to mention implementing it. I doesn't seem to have much impact to my reading. The scrollable things I use is the browser and a PDF reader. Firefox scrolls smoothly, while the PDF reader doesn't, but my experience reading with both is about the same. So I sympathize with devs who put their time into solving other problems.

I'd be interested in hearing from people who feel the opposite.