I guess if you disable z2t by default, like tromp just said, they would kind of be forced to do allow depositing / withdrawing 'private coins'. With Zcash, they kind of have the power of choice as it's a lower marketcap and it's technically possible to go from shielded to transparent. But if we disable this on the by far biggest market cap asset by default, they kind of have to follow suit.
Or they would just delist Zcash from this exchanges, and they don't have to explain why.
I don't like Zcash for several reasons, and it has even worse history than monero, but some security experts like Edward Snowden thinks it's good for privacy.
Lightning Network is fine and more people is using it, but I am nor sure it's the best option for for transacting large amounts of money, and we don't know what tech Chainalysis and others are using from tracking.
Sad thing is that most people don't care at all about privacy until it's to late.
