This might be out of date now, but 10 years ago I purchased a couple of monitors for a digital display. IIRC the monitors were more expensive because the screen wouldn't "burn" in images if left on the same image for a long period of time.
Edit: I suspect an OLED digital sign WOULD burn in though as I imagine that content is much more static and displayed many more hours per day. I just wanted to make the point that I do not fear OLED for common consumer use cases.