This might be controversial but hear me out:
The idea of an international independent currency that can be made use of anonymously and therefore not controlled by anyone is a great idea.
Most smaller coins are just scams, reimplementing the same protocols that earlier schemes did and eventually adopting a clear pump & dump characteristic.
However, I personally believe that bigger coins like etherium that don't fold as quickly and stick around are genuinely a good idea.
Moreover, there's use cases where transactions are tracked for different systems, for example tracking an interconnected energy grid and usage of households.
And then you also have to consider that block-chains themselves can just be used to keep a fulsome record of something, with the main goal of decentralizing control over that record. I'm sure there will be quite a few use cases for it that make more sense and it's quite a shame the stigma of crypto got attached to it.
If you wanna learn more about how block chains are actually researched, you have to dive into academic publications, but then you will find out scientists have a very different vision for this technology which is way more useful. And for the sake of actual science, I hope they don't get buried under the stigma of crypto, because oftentimes these are just very smart people with lots of passion for something that they genuinely see value in.