The 10 ball is squarely in the way of getting the CB behind the 5 off the footrail.
I don't really think the 4 ball is the important part of this shot; I think against the top of the stack is the only reasonably high percentage way not to sell out here.
Also, with how close the 1 and 4 are, you're not going to be cutting the 4 ball much no matter where you hit the 1, and even though you will cut it a little, there's going to be some throw that cancels out much of the cut angle. It may not get in front of your pocket, but I do think it hits the long rail above the 5. If it comes off the top of the 5, so much the better. Even if it sticks in front of the pocket, I think it's still a good shot, because of how tough the leave is.
-Andrew