How does it waste money? This aircraft is being added to the fleet so it had to be repainted anyway. I don't think blue paint is more expensive than red.
There also seems to be some logic in differentiating the liveries of their aircraft used on the subcontracted all-business class scheduled services for LH/LX/KL from those with VIP interiors used in their charter operations. The typical customer who can afford to charter a VIP 767, 757 or BBJ may also prefer a more subdued, discreet livery than red.