What is the reason for automating download links in websites? 

It could have the benefit of sparing the user a click, except that the browser *always* blocks it (you have to click on the yellow bar that appears at the top of the browser). That's harder than just clicking on the link that says, "If your download doesn't start automatically, click here."

If I'm building my own website, should I be concerned about adding this kind of automation? It doesn't seem to me like it adds much value, yet many websites do it anyway. Are they doing it because everyone else is doing it?