Storing and managing access to sensitive data offer all sorts in blockchain is theoretically a good idea, imho. In practice, it has many vulnerabilities (like every technology) which wouldn't need to be secured: https://www.ibm.com/topics/blockchain-security
Not sure if those vulnerabilities make it a much worse solutions than handing such data to Amazon or Google.
Anyway, I'm pretty sure blockchain in some form will dominate major public and economic sectors whrn I'm old. In countries like China or India probably much sooner.