We don't know much about the samurai suit other than the fact that it's a pretty notable object in the artifact room. During my visit, I got to witness a pretty fun sequence that proves the samurai suit will play a pretty big role. In the scene in question, Judy and her babysitter, Mary Ellen, are walking down a hallway in the house. The samurai suit is smack dab in the middle, perfectly still, but the hallway is too narrow that they must sidle around it.
As Mary Ellen scoots around the suit, it follows her with its head, like it's watching her. When she gets to the end of the hall, she turns around to give it one last look. That's when it whips its head around to look directly at her. Naturally, she jumps and hurries away.
It's unclear if the samurai suit will actually animate and behave like a real person at any point in the film or if it'll just sort of appear in strange and unsettling places. Either way, get ready for it to send a chill down your spine.