Rear tires also need to produce driving and braking force. The large drive/brake paddle on that minion 2 will help achieve both, plus you still get the side knobs of the DHF for cornering. Trade-off should be more drifting in stand-up off camber situations.I'm guesstimating here, but I think the cornering forces are higher on a rear tire than a front tire.
Which means a rear tire needs to be able to corner just as hard or harder than the front (unless you want it to be drifty).
So really, the rear tire has a lot more work to do all around (and why it wears much more quickly).
Given that requirement, I'm not really sure why you wouldn't want to use a really excellent rear tire in the front as well (or vice versa). I generally run the same tire front and rear.