Crystal and Ruby do not even remotely have the same semantics. They look similar but the similarity is extremely superficial. The extra semantics that Ruby has have a massive impact on performance, for even the most optimising implementations. This is not a reasonable comparison if you do not consider the 'slick as Ruby' part. No runtime metaprogramming! The entire Ruby ecosystem is built on runtime metaprogramming!
(Crystal is a fine language and compiler - but it's nothing to do with Ruby.)
(Crystal is a fine language and compiler - but it's nothing to do with Ruby.)