This means that when the music stops, someone ends up holding a big bag of nothing, since there's no backstop.
Melting gold down would require more energy, not less and is a step in the initial mining of gold, not "getting the energy back."
Not sure what you were getting at here
When the music stops, your account in the global open distributed ledger is stored in hundreds of thousands of harddrives distributed evenly throughout the entire free world.
And when the music starts again, your account is still exactly where it was when it stopped, available to you wherever you want to go in the free world.
I don't see why this is a problem, but if you want to use this as an argument, then go for it.
("Actual value" in dollar terms I assume? correct me if I'm wrong)
Current iterations of crypto have a cost to produce, which makes it valuable on the upswing since it is scarce. But there is nothing to catch it on the downswing, unless it is backed by some assets, and then you have to trust the backer, much like you have to trust any government. At least you can vote out a government though.