Bitcoin is implemented and most of the cryptocurrencies that we know today are created over the blockchain structure, because cryptocurrency became blockchain's first application, it does not mean that blockchain is only meant for cryptocurrencies. There are more applications.
You can try to use blockchain for whatever you want, it's a free world, but originally, blockchain was just a part of Bitcoin protocol created by Satoshi. And Satoshi never called it "blockchain technology" or talked how he can use blockchain in other fields. To him, it was nothing more than an implementation detail of Bitcoin. So, blockchain quite literally was meant for Bitcoin only.
Only later other people came and claimed that they can make something other than cryptocurrency with it, but they are actually yet to prove that. There a ton of hypothethical blockchain uses and very little finished and successful products.