Regarding 1, I agree that machine code (and machine-code equivalents) for probably all architectures are not Turing Complete if we are to be rigorous. In that

Regarding 1, I agree that machine code (and machine-code equivalents) for probably all architectures are not Turing Complete if we are to be rigorous. In that case, regarding 2, any encoding from a Turing Complete language into machine code must inevitably be an approximation. That says nothing about the source language. Regarding 3, I mostly agree - if you can comfortably accomplish your task in a language that is not Turing complete, then making the language Turing complete is a bug not a feature. That is true whether the task is programming or markup. I would say that HTML is not a programming language because it is not very good for programming; it is a markup language, because it was designed for markup and is much better for markup than for programming or most other tasks. Turing completeness is irrelevant.