The way I read the article, the “worth millions” is the sum of the ransom demand.
The funny part is that the exploit is in the “smart” contract, ya know the thing that the blockchain keeps secure by forbidding any updates or patches.
I do see potential use for them, but not in the way they are currently being used. I could see uses like door keys, tickets, memberships, etc being of practical value, but not stupid little pictures.
Besides the obvious of your door lock needing to be connected to the internet, and that could be a problem, what else do you see as being an issue with using it for door keys?
How exactly would that work? Keep in mind that the blockchain is by necessity not secret.
Another question is: why would you need it for a key?
Long-established public/private keys and signatures are used in this way all the time to control access to servers around the world. No blockchain needed. Blockchain is helpful when we all need to agree on a series of events.
Homes are a nice example of where you can have an isolated system which knows what it needs to about you (e.g. a public key) without sharing or cross-checking anything with the world.