Ella to me is a nickname for
Eleanor, not for
Elizabeth. This is just my opinion. I dislike
Elizabeth nn
Ella just as I'd dislike
Elvira nn
Ella or
Elysia nn
Ella or something. It just seems far fetched. I also can't stand stuff like
Persephone nn
Poppy or
Aviva nn
Ava. They just don't make sense to me and I think they don't to most people. After all
Ella is extremely common on its own but I've never met an
Elizabeth who was nicknamed
Ella. I've met one
Eleanor nn
Ella. It might have worked centuries ago but I think nowadays people would be confused.