I've been seeing this floating around on social media. I wonder if this was an actual design feature, or it just so happens to work...well sorta work. I tried to get a wrench on an old Craftsman PH2 and it doesn't really fit all that well, even if it did fit I'd be afraid to put too much torque on that plastic handle. Although now that I think about it, a Philips would probably cam out way before the handle lets go.
It would be interesting to see some of the original patents to see if this was actually a purpose built design.