There are definitely some core accessibility features that are great for non-disabled users, though, for example having text descriptions for images (it always irritated me that alt-text didn't automatically generate a tooltip, though I sort of understand why)

It's great to be able to mouse over images in Tweetdeck and (if the poster provided it) have the alt-text pop up in a tooltip so I can scan it to see if it's worth the time to open the image, and it's great to have textual descriptions of toolbar icons.