Before a trade on a visible book ever fills, the market has already read your side, your size and your price. On a chain, that reading is free, instant and automated. kn:ll exists because that arrangement is indefensible for anyone trading real size in tokenized equities.
Put a 5,000-share buy on a public on-chain book and three things happen inside one block. Someone buys ahead of you and re-offers higher. Someone lifts the ask you were about to hit and sells it back to you. Someone reads your limit and quotes exactly one tick inside it.
None of this is illegal on-chain. It is simply what the book invites. The cost shows up as slippage you attribute to "the market". It was not the market. It was your order, read aloud.
On thin, chunky assets like tokenized stocks, that cost dominates. Being seen is more expensive than being slow.
Three properties make them the worst case for a lit book. The reference price lives off-chain, so on-chain quotes are always stale and always gameable against the real NBBO. Liquidity is thin, so a single resting order is a large fraction of the book and visibly moves it. Size is lumpy: institutions and treasuries move blocks, not dust.
Put together: on-chain equity books are where the largest, most legible orders meet the fastest, most automated readers. A dark pool is not a luxury there. It is the only structure under which size can trade at all.
Dark does not mean unregulated, anonymous to counterparties, or unverifiable. It means one thing: no information about an order is available to anyone before it fills, and no information about an unfilled order is ever available to anyone.
Everything else is bright. The reference midpoint is public before each round. Every fill is published with size and price. The matching proof is public. The committee's behaviour is logged. You can audit the pool; you just cannot read the pool.