Hosta's give shade to many insects throughout the Summer and are excellent pollinators for bees. They are also recommended by the RHS for gardens in the UK. So I'm surprised by your comment Michael.
It was tongue-in-cheek . . . hideous things. But if they're good for bees, they're also good for slug food :-) But equally, they are invasive non-natives in Europe, so don't belong in healthy ecosystems here. Different matter in eastern Asia, of course.