Probably Attorney Frye has more experience in arguing before appeals courts than does Attorney Powell. I'm on the fly right now and do not have time to Google Attorney Frye but if someone has time to Google her I think you would probably find that she has a lot of experience in arguing before appeals courts.
I am not a lawfag yet but I'm going to be one soon. In my experience appellate work is trickier and more detail oriented than trial court work therefore appeals are usually argued by attorneys who have more experience before appellate panels.
Just my guess. I take this as a good thing, not a bad thing. And I still think Sidney rocks.