I don't think that the flies are beautiful or anything close to it, but you captured the moment nicely.
I think most of us will agree, when I say that the flies are harmful, dangerous and irritating.
Not by their looks, but by their actions/doings and sounds.
Flies are often carry and spread diseases, bacteria and their sound is irritating. They land on your/our food and infect it.
More info can be found about them in the following articles:
Fly - Wikipedia.
Flies carry even more disease than we thought - CNET.