That's a poor explanation mostly because Satoshi was not a cryptographic expert, at least not at the start. For example he insisted early on that you can't use

That's a poor explanation mostly because Satoshi was not a cryptographic expert, at least not at the start. For example he insisted early on that you can't use elliptic curve cryptography for encrypting messages (wrong), he stated that he had to research ECC because there was very little information out there about it back then, and so on. More importantly all actual cryptographers were trying to build e-cash systems out of novel mathematical constructs. Bitcoin ignored all of that. It just uses SHA2 and digital signatures. Cryptographically it's as plain vanilla as it comes, and lots of developers understand hash functions and signatures. There's no actual expertise required to use them.