The main usage is with compound words such as "ice cream" or "Louis XIV" or commercial phrases such as "Camry SE" where for esthetic reasons an author would prefer that the space not expand upon justification,
Given wide enough measures, good text layout program should be able to produce justified text without very noticeable changes in word spacing.
NBSP doesn't break, but should it justify?
I believe NBSP should be, to the reader, indistinguishable from a regular space. It does not have a semantic function as a compound- word-joiner; it's just a space that doesn't break, and therefore should be treated like any other space.
~fantasai
