It has been into PS for a long time. For
rescaling down has some properties: it keeps the SNR (other algorithms improve SNR) and enhances sharpness without producing any hallos.
The drawbacks are that it generates terrific aliasing artifacts when geometrical patterns are present in the scene.
For Web rescaling down it is nice to try the following:
1. First rescale with Bicubic to twice the final desired size (e.g. if the final JPEG will be 800px wide, rescale with Bicubic to 1600x)
2. Next rescale with Nearest neighbour (it's called Aproximation on the Spanish CS2) to the final size: 800px
This gives good sharpness for natural shaped objects and landscapes:
Not always works.