Director gets its animation speed and smoothness from compositing all graphics to an offscreen buffer, and then blasts the contents of this buffer to the screen. This DIB driver, and other variants such as WinG, all work at 8-bit in Windows 3.1.
Director displays images differently than a painting program.
Even on the Mac, where high colordepth video drivers have been standardized for years, most developers use 8-bit graphics for speed in loading, storage in RAM, and speed in making compositing calculations, in addition to compatibility on the widest range of machines. Some older applications can display multiple images at higher colordepths. These are device-dependent bitmaps, and there is usually very little compositing or animation that can be done with them. There are also stability issues, because performance varies with the video system. The older Director Player for Windows used DDBs, was supported by fewer video drivers, and could not support all ink effects.