The only reasons it is different with houses is because people are emotionally invested in them, not all houses are equivalent (and thus their value is unique per house), and liquidity is hence really low, and market prices adjust slowly.

Bitcoins are worth a thousand dollars because people who own them are not willing to part with them for less, and people who are buying them are willing to pay that much. This is economics 101. You can always cash out at the market price, unless liquidity is low; the only time that happens is in a teeny market or a crash.

It's only easy to buy a house for $100M if you have $100M you can spare for house-buying. And then you only get to choose from the rather limited range of $100M houses that are available for sale.

Similarly, you only get to sell a house for $100M if you have a house that nice to sell. And then you only get to sell to the rather limited range of people willing to buy a house for $100M.

But perhaps I've misunderstood. If you happen to have $100M burning a hole in your pocket, it's easy to buy a house that would normally cost $1M with it, because most people with $1M houses will happily sell them for $100M. But the parallel to that is that if you happen to have a house that would normally cost $100M, it's easy to sell it for $1M. Which it would be.

With the exception of Mt. Gox, this is simply not true. It's hard to both buy and sell Bitcoins if you've not been verified at an exchange, but once you do that (not very hard), it's equally easy to both buy and sell. The only delay is the time needed for the wire or ACH to arrive.

I get the feeling that many of you are talking confidently about something you have no experience with. Where are you getting the idea that it's hard to sell Bitcoins?