You mentioning the video ad thing actually just changed my mind. I always used to think "hey free wifi is free wifi" but having to stand there and wait for some ad to finish before you can even check your gate... that totally kills it when you're in a rush. It really does ruin the whole point of having it.
Got stuck watching a skin cream ad last time I tried airport wifi. My flight was boarding and I'm just standing there learning about lotion. Pretty sure I missed my call to board because of that.