"crypto" is a very wide word, there are a lot of technologies participating in the game, and a lot of technical details in them. Most are completely irrelevant to most regular people.
Blockchain is pretty simple. There's a database, organized in a way that you can add records to it but you can not edit past records - or if you try to, everybody would know you did. There's a network of people maintaining this shared database, as a payment ledger - basically, this database for them says "X has $Y amount of database-money". People participating in maintaining this database get paid in the same database-money. They have incentive to do it properly, otherwise their database-money aren't worth shit. They also have incentive to steal if they could, but since they can't edit the database without other people noticing (who aren't interested in having db-money stolen from them) it's hard. That's the basic level of cryptocurrency systems, very shallowly and simplified, of course. If you want to know the math and protocols, there are full college degree programs dedicated to it (I am not kidding at all, there are). There's even free courses on Coursera and such which deal with the basics.
The second level is allowing to do other, more complicated stuff with the same database. Like keep ownership records for other things (that's basically NFT). The next level is turning it from passive database into a computation engine, so you can make computations that will be reproducible over the database. That's ethereum contracts and such. There also side aspects - like privacy chains, where the information who owns the money is encrypted, so you can prove you own the money but somebody else would have hard time seeing how much you got and where it came from (it's usually very easy in most chains). Etc. etc.
Whether it's revolutionary or overhyped - I have no idea. That's kinda societal question, certainly all the above (and more) can be useful and you can build useful stuff on top of it. Would some people use it? Probably. Will everybody switch to it from existing ways of doing things? I have no idea, but I suspect no. But I am nobody, so it's worth nothing. A lot of people smarter than me thought there's a use case for certain things, and spend a lot of time and money building stuff, and nobody every used it. Take Meta - the whole "metaverse" thing, nobody even remembers it now. There are many things like that. Is crypto one of them? I dunno. We'll see.