Why did Commodore put monochrome video output on A500/A2000?

[Britelite]

A500 composite is 64 shades of gray easily displayable at once from a palette of 4096 gray shades.

Using HAM mode or raster interrupts one can get all 4096 shades on screen at once.

Sorry, but you won't get 4096 shades of gray out of the composite output

[Britelite]

Sorry, but you won't get 4096 shades of gray out of the composite output

Why not?

Because the way the monochrome composite signal is built, which is (according to the Amiga Hardware Reference Guide) 30% Red, 60% Green and 10% Blue. And with 16 levels of each color component you get 151 unique shades of grey. And considering the quality of composite output in general, I wouldn't count on all of those shades being distinguishable from each other