Right. I was only thinking that if U+202F wasn't available it might be a better choice than NBSP.
I checked some common fonts which confirmed what I believed, that digits are normally equal in width to the lowercase letter _n_ or very close and that a normal space (and non-breaking space) is half that width.
Accordingly U+00A0 (very, very rarely not available in a font) seems a better choice than U+202F.
U+202F as a digit-grouping space would be double the width of a normal word-division space, separating the parts of a single number more than words are separated, equal to sentence division if one is double spacing following a sentence.
Of course in justified text both normal space and non-breaking space usually expand in width to enable line-filling and might so the digit-grouping space might sometimes expand to a width greater than the digit-width in that font.
But even in such a case the digit-grouping spaces would still not be greater in width than word breaking spaces in the same line.
U+202F which is always a wide space would be generally less desireable than ordinary non-breaking U+00A0.
Jim Allan
