Question: Why does Wonder Woman need the armor?
Rob245Answer: When Barbara Minerva wished to be just like Diana, she was granted the same strength and powers as Wonder Woman. Barbara additionally became less humane and more dangerous, particularly after she morphed into "Cheetah." Diana needed the armor to outmatch and defeat Barbara. She was also expecting to fight a multitude of soldiers to get to Max. The armor was originally Asteria's, who needed the extra protection when she battled an army to save the other Amazons.
raywest
Answer: This was not explained in WW84, so any answer would be speculation. It is rumored that Lynda Carter, who played Asteria, may appear in Wonder Woman 3, which will hopefully explain her backstory. She is probably similar to Diana, who also chose to remain among regular people, secretly using her powers to protect them.
raywest