The tree’s nutrients need to be transported through capillaries. And this  part is easy to absorb the water from atmosphere from air which lead to mold.

Spraying lacquer on the surface can  blcok the capillarity, stop the product get “wet” and mold.

While some other prodcut are only spray oil on the product, the capillarity still have the chance to get water from air.  when the product get some water on it,  it would be better clean by dry towel and placed in the dry place. Otherwiese, the product will the risk of mold.