I still wonder that exchanges like Coinbase do not have proof of reserve yet but many people trust the exchange. Kraken and Bitstamp too are not small exchanges and they do not have it yet.
Probably because proof of reserve isn't the primary consideration when users choose which centralized exchange to trust. And rightly in a way, because these proofs, popularized by Binance if I'm not mistaken, don't really prove much. Kraken, for example, didn't submit theirs because they see no point in this
financial reserves thing shown in Coinmarketcap.
If I were an exchange and I provide an address that has $1 billion in Bitcoin in it, what does it actually say? It can be verified by anybody, yes, so what? Does everybody know as well that my liabilities actually total $2 billion? But supposing I'm also providing a breakdown of my liabilities and it totals $800 million, would that be enough? Still not. How would you know that I included all the deposits? Even supposing I included everything, how can you be sure that such an amount is really owned by me, or that it's not offered as a collateral or something like that, or, in short, that it isn't encumbered in one way or another?
All I'm saying is that this proof of reserve thing is not really the "Don't trust, Verify!" kind of thing.