24w33a introduces new experimental changes to redstone dust, aiming to fix some of the long standing issues with it, like the lag it causes and the unintuitive and unreliable way in which it updates.
The problems with redstone dust stem from its naive implementation. When a wire is updated, it checks what signal it receives from surrounding blocks. If that is different from its current signal strength, it updates it and then notifies neighboring blocks. This implementation is fine for individual wires, but when multiple wires are connected, its flaws become apparent: the wires power each other, but the signal degrades over distance. Thus when you remove the power source from a line of wires, the signal will die out completely. However, any individual wire does not have this context. It will only decrease its signal strength to match what it receives from neighboring wires, and that will repeat until all wires have depowered completely. This r