Nice article, I just wanna point out a couple things. Privacy is absolutely needed in this world - how can you doubt it? If I run my business on the blockchain I don't want competitors to know how much I pay a programmer or how much a vendor charges me.
Second point is that privacy does not need to sacrifice ANY functionality. The idea behind zksnarks is that I can conceal the details I want to. I can prove, say, that I have enough funds at an address to cover $1 million USD worth of expenses without revealing the actual balance.
The problem is that privacy being optional (I assume you were referring to ZCash in your post), all private transactions automatically stand out, and the anonymity set is much smaller.
Yeah that's a common criticism of Zcash - people won't deliberately do anything, and most will use the transparent addresses. Not convinced it matters though - there's no clues, even if the anonymity set is small.