And not only that, but when only one front wheel is on the ground as with an IFS rig, those CV joints/bearings are supporting the entire weight of the front end!
You just answered your own question! The live axle allows both tires to contact the ground due to the suspension pivoting (or counter-balancing, as you mention). Naturally, tire contact=traction, which is good! I guess on an IFS rig, you could have diff locks to fix that problem, but the tires...