It looks cool with your practice jersey on, but that’s about it. I’ve used one the last two years. We just got new pads, and I don’t think I’m going to put a plate on. Just don’t see the point. As far as protection, who cares? You shouldn’t be getting tackled from behind anyway. 
BTW, has anyone used those girdles with the built-in foam thigh, hip, and butt pads? I hate leg pads and never wear anything but very small thigh and knee pads, but I’m always worried about getting flagged.