My interest is in the zerocoins. The IP obfuscation is claimed to be needed for them also, because ZC doesn't hide your meta-data from externalities (how could it, it is only the block chain and not the entire internet). But it does afaik prevent your meta-data from being correlated with any UTXO because UTXO are entirely obfuscated in a blob in ZC (except for one very unlikely attack mentioned in section 6.4 of the white paper which I think can be foiled/detected). But that claimed need is only because you don't want your payer IP address to be revealed to for example the payee. But the payee is likely to know who you are any way. And other nuanced scenarios like that. And not just IP address but browser cookies, etc, etc. I think externalities meta-data is an insoluble issue. Can never be reliable.

Thus I reason that the more certain markets are those where the corporate server is very much in control of its meta-data footprint and the superior provability of the ZC obfuscation (no publicly detectable UTXO!) wins.

Any way, I don't want to spend too much more time on this, because I am not developing in this area any more (unless something changes in my plans). I wasn't impressed that I was banned from the Zerocash forum about 3 minutes after I posted there, lol.