Bennifits of having both systems?

I have a ps4 right now. My sister wants to play just dance. She was just going to pick up a wii to play. My bro was like no let's get an xbox one because of connect camera is good. I said we could jsut get the game for ps4 lol but my bro says no because we can play all the games now. So is there any bennifits that I am not getting on my ps4 that having an xbone would help?