This only makes sense as far as resource usage goes, Turing completeness has nothing to do with access to APIs which you really need to do anything interesting.

This only makes sense as far as resource usage goes, Turing completeness has nothing to do with access to APIs which you really need to do anything interesting. Brainfuck is turing complete but can’t call any APIs, you can very much predict that a Brainfuck program won’t be doing anything very exciting.