This is a perfect example of how nebulous #screenReader #accessibility is, and why it confuses so many laymen. I am looking at a web page right now that has a "Download" button. The button is an a (anchor) tag, with a div inside of it with the CSS class for a download button.
Obviously this is awful HTML, but it works fine, if you can see. There's a big fat button with "DOWNLOAD!" in all caps on the screen. Clicking this button starts the download. Seems good, no?
Well, no. This div has no actual textual content, and the anchor tag has no href or text either. So this huge honking button is entirely invisible to screen readers. How do I even begin to explain this to, say, a customer support rep? :)