I've never seen a V4 character that didn't have her brows as part of her face texture. (But I went right from Posette to V4 with many years absence in between).   So I don't know the benefits of transmapped brows. I do know the damn eyebrow zone is a PITA the way it keeps reappearing in all its shiny plastic glory. Maybe if I had some trans brows this would not be an issue.