Of course they can, however I was describing the advantages of crystal as opposed to go.

Crystal vs Ruby don't really compete in the same way Crystal and Go do, it's very much a dynamic vs static typing split. Crystal is in general a bit more cleaned up but Ruby's community is much larger.

That still comes at a cost. The macro/lazyeval approch is usually seen as "zero cost" because the JIT engine usually only spends time inlining if it's a hot block.