Raspberry Pi is a general computer and can do general computer stuff. You don’t have to use the special GPIOs for everything. So why not use it for digital signage: It has a HDMI output so uoui can put a screen or TV of almost any size on it. Our smallest HDMI display is 10″.
Digital signage can be made with different sources: You can use a browser in kiosk mode (not showing menus etc) to show the content of a website somewhere or you can let the Raspberry show some local content, Much in the same way as a digital picture frame. And of cource you can also start the webserver on the Raspberry and use the browser to display local content.
For technical reason you might also distinguse between images and videos. Or even live videostreaming.
Binary Emotions has made some systems to do exactly this: http://www.binaryemotions.com/digital-signage/raspberry-digital-signage/
So you can start up using digital signage for your shopwindows, your reception area or your meeting room for a mere 1.000 kr plus the price of whatever screensize you need.