As quoted from your source:
Instead of obscuring the entirety of a blockchain, bulletproofs only conceals the quantities sent within a transaction – the sender and recipient’s address are still visible, but the amount being sent is not. And while it’s not total anonymity, the confidentiality added with bulletproofs can be handled by already operational blockchains, said Bunz. [emphasis added]
From what I understand the enhancements to ZCash due to come later this year will make zero-knowledge transactions much more efficient. ZK proofs are private, very much so, and completely. Any type of transaction which exposes either the sender, receiver or amount is not private. Period.
NB: It’s also noteworthy to point out that the article then talks about ZK transactions and the fact that it’s not “trustless”,
But it’s not just the lightweight confidentiality that makes bulletproofs so attractive. It’s also in the fact that the tech doesn’t require trust in others, like zcash’s zk-snarks tech does (the reason for its elaborate generation ceremonies). And, while the trusted setup is getting increasingly more secure, the process is still much criticized.
(Hello, Zooko…hopefully a positive press piece is in the works about the “Powers of Tau” ceremony and how this will should make ZCash a trustless platform).