GHCi is super useful for quick checks (is `round 3.5` 3 or 4, what is `(-9) div 2`, what's the type of `(.) . (.)`, ...). But its slow to start and a huge install. rhci is a small version of GHCi that exactly matches GHCi semantics.
rhci runs standalone on on x86 and ARM on Linux, Windows, macOS and the BSDs via a cosmopolitan compiled mruby. Or anywhere CRuby runs via a single .rb file.