Know what's cool about superconductors? They have zero impedance. Not low impedance. Not very low impedance. No impedance at all. There's a very real difference between something being a super bitchin' conductor and something transmitting an electrical signal or electrical energy with absolutely no loss. Copy an album onto tape using the best gear imaginable. Then copy that tape onto more tape. You will experience generational loss. Now - copy a CD. The data is the data is the data and once your error correction takes care of entropy, the bazillionth copy will sound like the millionth copy will sound like the first copy.

There’s plenty of ways to architect a database that prevent modification.

"Prevent" is not "prohibit." When you "prevent" modification you depend on a layer of trust: you trust the guy with the keys, you trust the software he's using, you trust the keys you've handed around. When you prohibit modification you no longer give a shit about any of that because no matter what they try it's impossible. If I say something, and the consensus of nodes agree with me, it's true. Better yet, any node that doesn't agree with me is no longer on the network. You either accept the consensus view or you get ejected from the party. Forgery simply doesn't happen anymore: if you want to alter something to suit you, you must get the majority of sites to agree to your alteration. Now you own the blockchain. Was it worth it? Because the people who disagree with your alteration might be a minority, but if they've got enough to convince everyone else, your blockchain just got disavowed anyway. Ethereum Classic is now what? Four years old? I dunno, I don't go to their parties.

There's a difference between "things people trust" and "things that are without requiring trust." It's a fundamental change to the way we mark stores of value and stores of data. This is usually where the conversation devolves into "what is money" at which point the coders tune out and say "navel staring morons blockchain is worthless" and the libertarians whip out their copy of The Creature from Jeckyll Island and beat people over the head with it but it doesn't change the fact that the advent of networking and computation has fostered a system for marking value that is fundamentally different from anything we've ever had.