A plain old database also has ways of dealing with theft.

If someone steals your crypto keys and sends your assets to themselves, they have no legal ownership over those assets but they're listed as the owner in the blockchain, so blockchain isn't even any good at being an accurate, verifiable record of ownership.

Yes, you can't make changes to the blockchain, but that also means you can never fix anything. So you actually can't rely on the blockchain to be accurate.