If you have ever heard Billie's first recording, "My Mother's Son-in-Law", you'll know that one of her earliest inspirations was Ethel Waters. I don't think Waters ever recorded that particular tune, but if you listen to Billie's reading of it, she sounds like a carbon copy of Waters, with the older diva's perfect, somewhat exaggerated diction. Billie would, of course, quickly drop that as she eased into her own individual style later on.
At her time, it was very common to cover songs. They didn't put out song after song like pop factories today and covering a song was considered a compliment. I love to hear the same song in different styles and voices =)
I deeply respect Ethel Waters for bringing Georgia on my mind to us and I enjoyed her style of singing. A cover is much more than just singing the same song. It's a unique musical art opportunity for the musician who weaves in their own expressive style. For me, Ray Charles greatly enhanced the song with his rich soulful jazzy style.