It shouldn't matter, but then again you shouldn't be using the non-breaking space character entity for separating words in the first place.
The only time I ever use it is if I want to add multiple spaces between text. Eg. At the start of a paragraph to indent the first line. I know there's other ways and this prob isn't a "valid use" but its quick and works.
CSS does the same thing. p {text-indent: 1.5em;} Code (markup): And as you can tell, uses a LOT less code than to indent paragraphs. (Oh, and it's a LOT quicker.)