Spotify doesn't make use of the OSX Accessibility API.
For my own uses, that's nothing more than an inconvenience - it just means I have to use the mouse more than I'd like to. But for blind or visually impaired users it must render the app unusable.
Update: This idea has been submitted again here:
This idea has been submitted more than 1 year ago but unfortunately hasn't gained enough kudos during that time (10 kudos/year). In order to keep an overview of the active ideas in this forum, this idea will be closed for now. Note that this does not mean the idea has been declined by Spotify.
Please feel free to re-post this idea if you still feel you want this implemented. With a little change in presentation, maybe this time it will gain the necessary support from the community.