OK here's a puzzle for you. Blockchain. Its immutable, for all time. And that's the point, its not a side-affect. So, that pizza you bought a few years ago with Bitcoin, someday digital archaeologists will puzzle over why you felt anchovies were the right choice for that topping. And yes it will be you, its not anonymous. That wallet ID is in there forever, its not like cash. (side note, there are crypto-currencies that are more anonymous, more like cash, e.g. monero).
Now, meet the EU and their GPDR. Specifically Article 17, Right to Erasure (right to be forgotten). This, in conjunction with retention durations, are fundamentally incompatible with many blockchain technology as it stands today. How long before there is a test-case, some person who bought a PDX Licki with Bitcoin files a test case under right to be forgotten?
I mean, this is a serious issue. Your friends are laughing at you, you secretly think this is what cost you that last job opportunity. So you want all digital records of this transaction forgotten. Its sort of the regulatory equivalent of tequila.
And then what happens? Some of those blockchain instances are for sure run in Europe. All of them process data on behalf of a European citizen. So they are in jurisdiction, right? Its just, well, it doesn't work that way. The blockchain is written, its shared, consensus, signed. Its not changing.
You may as well just post your selfie on the 'liki wall of fame', cuz that transaction is not going away.
But, for sure, many of the crypto-companies are currently flush with 'valuation' (not necessarily cash, an ICO makes you wealthy on paper, but you can't always liquidate that to fiat currency so easily). And this will attract
nutcases people with legitimate claims, and lawyers willing to get publicity defend the rights of the downtrodden.
I think we are in for a spectacle.