Ys, I agree with you.
Many people use avisynth, a nonlinear script encoding.
And these technologies are interconnected with after-effect.
And many avisynth users want the RGB32 when they do lossless work.
Initial after effect or fremiere was not connected to avisynth,
so they used x264codec in aftereffect or premiere to store as rgb.
And call back the result through avisynth and virtualdub to work.