transform = [S] * [R] * [IS] * [T]
Where IS is the inverse parent scale, which is pretty much all that most dcc packages do....
Certainly maya applies that transformation for all joint nodes, but geometry leaf transforms usually just use a plain SRT.
Speak to an animator, and they usually find a million reasons to support it. A common trick is to apply non-uniform scale on leaf transforms within a skinned mesh to prevent collapsing elbows, or to simulate the effect of muscles bulging. I've even seen rigs that have made use of excessive amounts of animated scaling for classic-cartoon-like squash and stretch. It does have its uses, which is why animators make so much use of it in maya et-al. A seasoned animator in the games industry may not use it at all, but that's usually due to them having been pre-conditioned to not use scaling on pain of death, not because it has no use.
I don't know what people use non-uniform scalings for anyway.