It's the psychology of it that I stumble over if it was incorporated into part of Film Logan, too. I could never really buy him wearing a costume in the comics either, unless it was intimidating, and the blue and yellow one just wasn't.
That one goes with the whole black ops feel of X-Force, and does make him look scary, which is honestly the only reason I could see him agreeing to wear it. I was always surprised he doesn't kvetch about 99% of the costumes he's had to wear more than he does in the comics. He's so not the kind of guy one can imagine being okay about wearing clothing someone else has picked out for him, especially spandex clothing.