1. Zcash actually has two types of addresses: one starting with z for strong privacy addresses (like wearing an invisibility cloak), and one starting with t for transparent addresses (everyone can see the transactions). It doesn't default to full privacy; instead, it lets users choose.

2. Currently, most people use transparent addresses: because most exchanges and platforms, to comply with regulations and avoid trouble, default to giving users t addresses. Very few actually need strong privacy.
3. Compared to Monero, Zcash is a bit "nicer": Monero defaults to full privacy for everyone, very hardcore, but also attracts close regulatory scrutiny. Zcash’s "optional" design strikes a balance between privacy and compliance, making it potentially easier to accept mainstream.
4. To give an analogy: Bitcoin is like HTTP (plaintext transmission, open and transparent); Zcash is like HTTP/HTTPS (can choose to be public or encrypted); Monero is like HTTPS (default full encryption).
In simple terms: Zcash’s privacy is switchable; currently, most people keep "transparent mode" enabled to cooperate with regulations; Monero is in "full privacy mode," more concealed but less welcomed by regulators.
Data analysis platforms (Arkham) can now track on-chain data for Zcash; over half of transactions can be labeled — which indirectly shows that transparent addresses are used more, while privacy features are actually used less. $ZEC $XMR