I think this is a pretty good mechanical design in general because:
- large contact surface (like hex or torx)
- no chance of slide-out (like flathead) or torque-out (like Philips)
- you can use a different size screw bit than the screw, and it wont slide around, or destroy your nut like torx does with hex
Just because there's a workaround for an unnecessary annoying thing doesn't mean the thing ceases to be unnecessary and annoying.