A 100% useful heuristic for "is blockchain useful here" is to understand that blockchains can be completely replaced, at much lower cost, with a database hosted by a trusted party.
If there is literally anyone that can be (or at least must be) trusted by all potential users of a system, then it's better to just use a database controlled by that person/entity. That's why blockchain-based solutions never pan out when it comes to interacting with the real world: In real life, there is a ton of trust required to do anything.
If there is literally anyone that can be (or at least must be) trusted by all potential users of a system, then it's better to just use a database controlled by that person/entity. That's why blockchain-based solutions never pan out when it comes to interacting with the real world: In real life, there is a ton of trust required to do anything.