The point of using TL's Bair is that with diminishing returns, you can weaken his Bair enough to make them combo into each other really well.
Wolf's Bair works on a similar level. It's great for KOing, but if you weaken it with diminishing returns, you can Wolf Wall (Wall of Pain, but with Wolf) people pretty well, as you can full hop double Bair easily.
ROB's Bair isn't that bad to RAR. It has great knockback, and it's perfect for spacing since it blasts you in the opposite direction.
Olimar's Bair is useful if you've weakened your Fair, but that would be the only real reason to RAR it.
Dedede's Bair is pretty much ****. Great to use if you've already chaingrabbed your opponent to obscene percents.
Oh yeah, Pit and Ness have crazy KO moves in a sweetspotted Bair.
Even if your characters don't utilize RAR very well, it's a valuable technique to learn in order to keep your playstyle unpredictable and less susceptible to diminishing returns.