But the signature is an encrypted hash value, which is decrypted when verifying the signature. Maybe you could say signature verification as a concept is not encryption, but certainly Bitcoin's implementation uses encryption, and I don't think there's any definition of 'asymmetric cryptography' that is not also some form of encryption.
I'm not an expert on BTC, but I'd guess that if you can derive the private key of a signature from its public key (which is what the paper is describing), you can use that to place transactions from said wallet on the blockchain (ie. spend that wallet's money), right? Genuinely curious if I understand this correctly, there's a lot I don't know about how bitcoin's protocol works.