Robustness is relative. You can certainly write a cli that does everything in an arena; your GC is the OS and so going out of scope -- who cares. doing nothin

Robustness is relative. You can certainly write a cli that does everything in an arena; your GC is the OS and so going out of scope -- who cares. doing nothing and eliminating whole classes of errors from consideration (UAF e.g.) is incredibly maintainable. Or, as the old tale goes, your GC might be the software literally exploding (it's in an air to air missile)