Most examples seem to be concerned with I/O boundary crossing ("why ports, why volumes, why envs".) Is that the reason a type-system is mentioned, to provide sa

Most examples seem to be concerned with I/O boundary crossing ("why ports, why volumes, why envs".) Is that the reason a type-system is mentioned, to provide safety, e.g. a firewall-like DSL, through documentation? More emphasis could be put on at least two other values: discoverability and compatibility.