You’re absolutely right that Bitcoin's privacy is flawed out of the box. Coinjoins, while useful, are not perfect—they are expensive, take time, and often leave detectable patterns on the blockchain that a skilled observer can analyze. As for Lightning, while it improves privacy for routing transactions, the receiving node can often still leak key information.

Why Monero? Monero was built with privacy as a core feature, not as an afterthought. Every transaction is private by default, combining tools like stealth addresses, ring signatures, and RingCT (Ring Confidential Transactions) to obscure sender, receiver, and amount. This means no additional cost, effort, or technical know-how is needed to ensure anonymity.

Regarding eCash (such as systems like Cashu), you’re correct that it can offer strong privacy once tokens leave the mint since transactions are not recorded on a public ledger. However, it has its limitations. Unlike Monero, it typically relies on centralized mints, which introduces trust and censorship risks. If a mint shuts down or is compromised, users lose their ability to transact or redeem their eCash. Dark markets, therefore, are unlikely to adopt eCash widely without decentralized solutions.

Why dark markets gravitate to Monero: It works. Full stop. XMR provides default privacy with a decentralized network and robust cryptographic assurances, without relying on third parties like mints. That’s why it’s not just used in theory—it’s actively the de facto currency for anonymous online commerce.

While eCash shows promise as an alternative for small-scale private payments, Monero’s trustless, proven privacy solution makes it unmatched for anyone serious about financial anonymity.