This coin is all about hype. Once the hype is over down it goes. Even if Musk will boost his toy as long as he wants one day he may get bored like all billionaires do.
This is the best point among all the other good ones you made. I mean there is literally no use for dogecoins and the owner himself called it as a meme so why would anyone believe it go higher? Just because of the hype!
People need to understand that the actual value of dogecoin was a thousand times lesser than it is now if not even lesser, and the token was not underpriced because it was meant as a meme.
And I like the point you made about accepting dogecoin because even if Tesla accepts dogecoin it does not change the fact that dogecoin remains useless and Musk could have accepted literally any coin from the market with a decent market cap. One can always buy from the market and sell to the market in real-time whenever they need.