Earlier in the film, we are told that Worst Wolverine wore the Xmen uniform out of guilt and to remember his lost teammates, Deadpool jokes about it.

In the finale, when Wolverine redeems himself, not only fighting to save the people in the void but also DPs universe, his chains (the suit) symbolically explodes showing that he is free of his guilt

Also this is a pretty good way of tying in the mandatory shirtless scene in a somewhat meaningful way even if it doesnt seem so at first in a movie full of call outs