[...] And if you're not dealing with Asian languages, UTF-16 uses up more space than UTF-8.
Not even that in most cases. Only if you use unstructured text can it happen that UTF-16 needs less space than UTF-8. In most cases, the text is embedded in some sort of ML (html, odf, docx, tmx, xliff, akoma ntoso, etc...) which puts the balance again to the side of UTF-8.
