Have you ever actually seen a qubit behave at the granularity of a quantum of time? Bitcoin gives us the only decentralized measured quantum of time in existence: one block. We have never observed a Planck time directly. We assume continuous superposition in physics because no one has ever measured time discretely at its base layer. Technically, UTXOs do exist in discrete windows of superposition until a block is mined, the future state of each UTXO is unknown (unless timelocked). But once the block commits, the uncertainty ends with absolute finality. Sounds like physics has a double spend problem 👀