No, because the vast majority of that 'value' has never actually been paid out by anybody. The real-world global economic damage is being done by the mining. The day the thing collapses will be a very good day for the global economy.
I dunno man, all those guzzling bitcoin datacentres were't paid for by nothing, they weren't built on charitable donations. There are bigger industries than bitcoin that are based on even more puzzling whims. What is value? Capital has always had its own ideas about that.
The energy thing by the way I'm less pessimistic about, the bulk of actual energy use that is problematic here is all about shifting heat about, heat is pretty useful. The most successful miners will be those that can make their energy use as cheap and sustainable as possible, so they'll be looking to things like geo-thermal, hydro and solar- maybe even nuke (thorium hopefully rather than apocalypse-ammo waste, and more likely if we're talking China or India based mining). Also talking about better designed datacentres, cooling techniques, chip tech. Currently our electronic technology amounts to tiny little cavemen bashing things with clubs on the electron-scale, plenty of room for innovation there I think, could even be bitcoin miners looking to increase profits that make future advances in low-energy computing- I'm not one to rely on capitalism and technology to save the world but you can bet that if it means profits then ways will be found re doing more with less at any rate. You can depend on greed that's for damn sure.
Also, ways will be found (and are being found) to exploit the heat itself, thermal energy is pretty useful, people on this thread have even testified to that, warming their houses with their rigs etc. I don't see miners ignoring opportunities to direct that heat to other uses. The expansion in energy use may ultimately become the consumption of other processes that generate or consume heat. A million monkeys looking for an angle, too early to say if they'll produce Shakespeare or just a lot of random strings but it's a technology issue, technology and economics. I already mentioned the use of bitcoin as er... flash-demand that can be turned on or off to absorb the output of power-stations that take a long time to power up or down.
Chinese datacentres running on coal- if the Chinese government can be taken seriously (and they do seem like a serious bunch, bankers in the West don't even get sent to prison when they fuck about, let alone get executed) then it looks like the days of coal-power are numbered in China, even if these issues are just weapons that factions within the vast CCP use to attack eachother it looks like coal is becoming more of a vulnerability to its protectors in China than a boon, coal powered bitoin business-plans may not be considered to be a safe bet in the long term. Something that annoys me though is when Westerners slag off China for all the waste it produces in making the cheap products that Westerners like to buy. The use of China as a whipping boy for the activities of the modern world is just really fucking lame. We're all responsible for Chinas smog problems, the degradation of its rivers and farm-lands, the health issues of its people and the general contribution of Chinese industry to global climate change, and yet it's China rather than the United States that (at the government level) has recognized all this as a problem that needs sorting. All this "China- Boo!" crap has got to end.
I find the subject of bitcoin and crypto fascinating obviously, but I wouldn't bother getting up on a high horse about it because at the end of the day we're only talking about money, even if you don't think bitcoin is itself a form of money we're still taling about money, dirty sexy nasty bloody amoral money. It simply cannot be a moral position either way.
"What will you do with your bitcoin Craig?"
"Ah it's such a revolution, I'm gonna pay off my debts"
"yeah"
"buy a nice flat"
"yeah"
"go on a cruise"
"nice"
"buy some drugs"
"fair play"
"pay some prostitues to pee on my face"
"er..."
"get that semi-automatic with the silver plating I've always wanted"
"um..."
"pay a guy to kill that man I hate and exploit the fuck out of people who are much poorer than myself and also whatever portion of the environment I can turn into luxury yachts"
"oh dear." awkward silence "but you can do all that with dollars Craig"
"yes".
Money and wealth is amoral, you won't find me standing up for bitcoin as a moral position or the (I now think) played-up role of empowering the un-banked etc (it's the
Power, stupid) or making out like Visa represents decency and and good sense on this thread. I humbly suggest that moralizing against bitcoin on the basis of whether it's a bubble or not just looks... I dunno, weird. On the basis of energy concerns ok fair enough but even there we're far from a definite conclusion because the technology not only doesn't stand still, it moves really fucking fast, it's very much a moving target iyswim, so it's worth following closely to see where it's going 'now'. If bitcoin is a disaster we still don't know in what specific way it will be a disaster, and if bitcoin is a bubble- well so is the incumbent financial system because absolutely nothing was changed about it since 2008. The question of "when will it all collapse" is better asked of the global wealth system as a whole.
Some people are going to be seriously burned by this, people who can scarcely afford to be. 
