Not what you would call pretty or cute, they certainly can bring a feeling of disgust. The Green Bottle Fly can be useful in forensic, medical and veterinary science especially those maggots that determine time of death.
Since this fly is associated with feeding on dog feces, our picnic lunches and decomposing plants or animals, they are what kids might call yucky. Almost all Google searches lead to eradicating them.
Watch them in the garden, they do a lot of good. They might even pollinate your plants or help you make compost.