The hard part of Denim was not making blocks faster. It was that speed broke time. Ethereum headers store timestamps in whole seconds, so at five blocks per second four out of every five blocks report zero elapsed time. Interest stops accruing. Streaming payments freeze. Order expiry stops counting. So @base shipped BaseTime. A millisecond component rides in every block as a deposit at tx[1], valid values 0, 200, 400, 600, 800, written to a predeploy, exposed as timestampMs on blocks, receipts and logs. The old timestamp stays in seconds so nothing existing breaks. Reading the spec you can see the shape of the decision: they could have redefined the field and forced everyone to migrate. They added a lane next to it instead. The quieter half is what left. Flashblocks are gone, and with them preconfirmations. You used to get a preview that could be dropped from the final block. Now every 200ms block is canonical, own hash, own state root, no reorg of a thing you were already shown. That is a different guarantee, not a faster one. One consequence nobody put on a banner. Fixed cardinality V3 style TWAP oracles now cover about half the wall clock they covered last week. Same slots, ten times the blocks. Somebody is going to find that the expensive way.