Well surely that same principle could be applied to many different financial models.... Sell it to make a profit or keep it. What is new in that?
You are wrong.... bitcoin does have as much intrinsic value as you would like to put on it. For example, what would you do with your $10, £10 or €10 notes if you could never sell them? By you alluding to bitcoin being some sort of ponzi scheme clearly indicates you have a very limited understanding of what bitcoin is.
I'm not an economist, but I still think that the "value" of something is what people are willing to pay for it at the moment. Please correct me if I'm wrong.
You could resell a loaf of bread if you want and maybe make a profit. You could also eat your loaf of bread if you do not want to re-sell it.
What would you do with your bitcoin if you could never sell it

NOTHING That means it has zero intrinsic value. The only value that Bitcoin has is what some greater fool will pay for it.