I see two conjectures: one is that the increased surface area plays better on the tongue, another is that the cheese ages better with a rough surface. The latter can be tested by eating from the grated surface immediately and comparing with eating from a surface that was grated the day before.

I think the issue is increased surface area. In the same way, Marabou sells chocolate in tubes where each piece has a large concave dimple in the top. True, it also reduces the packing efficiency of the chocolate and lets them sell a smaller mass of chocolate in the same volume, but that dimple does improve the flavour. I know from personal experience that putting two thin slices of cheese on a cracker side by side instead of one slice twice as thick in the middle improves flavour. Similarly, devices for making wafer-thin slices of cheese are popular in Scandinavian countries (and, interestingly, in the Cambridge Cheese Shop for giving people samples of cheese).


Another point is that cheese tastes better when left to stand out of the 'fridge for half an hour or so.