While I do feel this is clearly marketing, this also is discussed at length about how blue light is terrible for sleep habits. So, I can see how if someone is a person that watches TV up to bedtime, and even in bed, that OLED may be less of an impediment to sleeping.
Yes, turning off the TV 30 minutes or more before bed and not having it on in the bedroom makes a lot of sense, but I do think that if someone is watching a TV, then there is solid reasoning here, if not cast in a marketing sort of way.