I've been using the wire coat hangers for over 15 years on every R/C car or truck I've ever owned....reason is simply because on our monster trucks the associated bars will be to short. It's true I've tweaked a bar a couple times during freestyles but who cares? After 15 years of running my trucks practically into the ground Ive only tweaked a sway bar 5 or 6 times.
Wire coat hanger can be used for sway bars for the simple reason that a sway bar is just a metal rod with no other purpose. Which is another reason I don't use "factory" or "aftermarket" sway bars....They aren't supposed to be springy....they are supposed to help hold the truck upright during weight transfers by twisting towards the middle.....If you have a spring loaded sway bar, or a spring metal, they don't twist towards the center but more towards the link at the wheels. That causes an un wanted excessive rebound spring rate....
Long story short....If im going straight my sway bars serve no purpose....they just swing up and down with the ball links and do nothing until I turn, then the arms flex and twist at the center, which keeps my center of gravity where it should be and has almost no effect on my shocks. This is especially important for me since I don't use springs on my truck....Oil pressure is what suspends it...