there are plenty of good theoretical applications for blockchain technology
This is not true. Distributed ledgers allow for consensus without trust. That is it. Every other application of them is just a slower database. So pretty much all they are good for is digital money, but digital money with a hard throughput limit and no backing from any government. The rush to use them for anything and everything violates the most basic principles of good computer engineering, and there's a very good reason no one has created anything worthwhile with them besides money that can be used for crime.