Lawlu is not a quality ship because Grumpy cat and Ball of sunshine.
Lawlu is a quality ship because of the seamless teamwork, unwavering trust, and mutual protectiveness. (Looking at you Trafalgar-don't-tell-them-I-was-captured-Water-Law)
Lawlu is a quality ship because of how they were there for each other in their weakest and most vulnerable moments. Because of the respect they hold for each other. Because of the crazy they share. Because they took each other to the heights of the OP world. Because they are strong enough to rely on each other.
For all those reasons, Lawlu is a quality ship.
The fact that it's Grumpy cat and Ball of sunshine is a bonus.