The video is great. A shame that it's getting downvoted.
In fiction there's the concept of suspension of disbelief. Wikipedia describes it better than I could, but to keep it short - when you're reading/watching/etc. a fictional story, you avoid applying your critical thinking and logic reasoning to certain story elements, in order to enjoy it.
I feel like a similar but not identical principle operates with game mechanics. I'll call it here suspension of scepticism. That suspension of scepticism makes you willing to trust that the information provided or implied by the game about itself is factual, accurate, and relevant.
For example, if it shows you a six-sided die, you treat it as a fair die, and you treat your odds of getting a 1 the same as getting a 6, a 5, or any other number. You won't save the game, throw the die a hundred times, and see if it's actually fair or not.
Those "design lies" use that suspension of scepticism to deliver a better experience. And it works - for the reason mentioned in the video, it makes playing more enjoyable.
However just like the suspension of disbelief can be broken, so does the suspension of scepticism. It's OK if the game designer is a liar, but he must be a good liar; if you lie too often or too obviously, the player will smell the lie from afar, and the suspension of scepticism is broken. And with it, the enjoyment of the game goes down the drain.