Why they are Beneficial
As its name implies, these lady beetles and larvae eat fungus, usually powdery mildew on plants.
These lady beetles will find their way into the garden if plants have powdery mildew on them.
It is possible that the lady beetle may transfer fungal spores from its feet as it goes from plant to plant. Chances are the plants already have the powdery mildew on them, otherwise the beetle would not be landing on them. They possibly eat aphids as well.