Right now, tease messages on clothing don't parse %color, though they do parse %t. It would be cool if they parsed %color too!
More than that, it allows better coordination with dyeing things -- if the tease is 'I tug on my blue shirt with a smile', and I dye the shirt red, now the tease doesn't make sense any more. That's one of the reasons I think the %color substitution exists, to allow for dyeing objects.
%color does work in wear and remove, so incidental messages do have some precedent.