Don't want to get into an argument about crypto currencies, but the value proposition of BTC is different. What is not replaceable by a simple DB is it decentralization and resilience to attack, its resistance to seizure and its incorruptibility in terms of maximum supply (the digital gold / store of value narrative).

It's worth highlighting that there are distributed databases that meet all those criteria except "incorruptibility in terms of maximum supply". You're right to point out that there are a few very specific use cases that a distributed blockchain with multiple independently-owned verification nodes will satisfy and other more performant databases will not. Whether that makes them "valuable" like gold is left as an exercise for the reader.

Distributed is not the same as decentralized.

A decentralized system is a distributed system that still works _when nodes are owned by multiple different (even competing/malicious) parties_.

Exactly. In other words, a "trustless" system.

See the Byzantine Generals Problem[1].

[1] https://en.wikipedia.org/wiki/Byzantine_fault

yes, yes, I said that already: "...multiple independently-owned verification nodes..."