The bubble question gets a hugely emotional response.
Bubbles are when price >>>>>> any real value.
Right now the Australian housing situation is a very REAL bubble. Of course, if you ask homeowners who are buying up whatever they can, they think its fair value. Its not. Its a bubble and its starting to burst. Aussie banks just got downgraded because problem is clear to everyone not involved.
Cryptocurrencies are MUCH harder to evaluate. What is their value right now? Are they going to take over everyday payments globally? Are they here to stay? Will central banks try to shut them down?