It's sort of like how Nim was sometimes advertised as similar to Python but fast, even though the similarities were pretty surface level. And by having a low level alloc/free available and a principle of performance (it's the first section in their Guides) Crystal could pretend to be a mythical C or C++ replacement. I also remember likening it to Pony at some point, and/or Red, but when I went through a bunch of them years ago they all kind of blended together as just existing because of dissatisfaction (either with performance issues in Python and Ruby, or with various issues of C and C++) while not wanting to join an existing Rust/Go/whatever faction.