Why not? To my knowledge, you can do a 3x3 solve in a competition with one hand and it will still count as an official 3x3 solve. You could do the same thing with feet and 3BLD. It therefore seems logical to count OH as well as 3BLD and feet in the overall rankings for 3x3. If someone were to get a sub WR 3x3 solve, only it's in a OH event, it is still the fastest official solve of a 3x3, is it not?