I like the general idea, your independent of the system wide framework version and it still has this "one-click" install procedure (dropping the binary in your path). However, I guess this is also the negativ Part. Users don't expect that a single binary extracts itself to somewhere --> uninstalling the binary leaves traces on the system.
Definitely looking forward to try it out for elixir, wondering how fast the erlang/elixir startup really is.