Dodge is paid for with the ship.
Dodge also shows that a ship is more agile than others.
Whist that explosion has a chance of destroying that whitestar, he may be able to ride the shock wave a little, hence the dodge roll. If a slow and lumbering ship tried it, they would have to rely on their hull and their superstructure to hold off the worst of the damage.
Not the greatest argument, I know, it's almost entierly PSB.
And I have got to say that a 'Cat Attack' is evn more fun than a chainsaw, but it's a little random too.