Given that smooth sees the entire the financial world through a pair of cryptographic specs I suppose this glaringly myopic post is understandable. Lets spell out the 2 concepts concerned here.

Achieving Monetary Veracity through Public Consensus
User sees a balance in their wallet. User goes to blockchain.info to verify that its "understanding" of that address balance agrees with what their (potentially hacked) wallet is telling them. They also check other sources on the internet. The fact that the rest of the world can see that balance and that multiple other sources around the cryptocurrency sphere also report it convinces the user that:

a) the balance is genuine
b) the balance represents an indigenous part of the network money supply because we can follow an (albeit anonymous) monetary audit trail back to other similarly verified addresses on the network
c) following from (b), the address balance is substitutable for and equivalent to the rest of the money supply for that currency
d) their subjective opinion on points a) b) and c) is consistent with the view of all other network users

The aggregation of those four points across the whole network is what gives rise to the fact that a simple bunch of 'numbers' floating around can accrue exchangeable monetary value endorsed by public consensus.

Cryptography and ‘math’ are no substitute for public consensus. People do not get on planes because some engineer handed them a sheet of aerodynamic equations. They do so because they see other people getting on them and not dropping out of the sky like bricks.

Viewkeys and “What is an Audit ?”
This brings us to the wild idea that somehow the much vaunted viewkey is a vehicle for audit and "statutory compliance". When I first saw this feature I thought it must be some kind of joke. For a start, no compliance auditor is going to be convinced of anything when the veracity of the very transaction machinery itself can’t even be audited.

Secondly, compliance audits in the fiat world involve complex analyses of internal bookkeeping, tax records and mutual squaring of multiple reporting sources and banking records. They only have any statutory significance because there is a legal contract of ownership covering every asset including bank accounts. In crypto, no such contractual association exists between a legal entity and a blockchain address. Handing a compliance auditor a bunch of “viewkeys” is meaningless. The only type of audit which has any significance in crypto is the one that replaces the banking system’s role in the oversight of the financial machinery - i.e. the public consensus audit I described above.

In that regard and consistent with classic principles of audit going back centuries, we are talking about verifying 2 perspectives: [1] - the current state of balances, [2] - how they got there. In Bitcoin, this requirement is supported (for example) by trotting off to blockchain.info and verifying exactly those parameters: i.e.:

[1] - the originating address balance prior to the transaction
[2] - the destination address balance prior to the transaction
[3] - the originating address balance post transaction
[4] - the destination address balance post transaction
[5] - the documented transaction record and amount

Thats a transaction audit and the fact that it’s open is what makes Bitcoin a viable monetary medium independently of a trusted third party since public consensus can act as arbiter in its place. Ditch that and all you're left with is an encrypted bookkeeping program.