I like how it looks.

I guess this is the answer to most of it. But some people are being overly cautious because completely black and completely white is not 100% good. Besides, it's always more pleasing to the eye if the deep shadows are with little detail and the highlights are not completely blown out. The human eye has so much bigger dynamic range than our cameras that keeping the detail in the extremes kind of emulates what we see. But more than 10% is useless anyway.

Check this:

http://www.modelmayhem.com/po.php?threa … st15855107

I remember in the old days of Crosfield drum scanners and offset printing, they tried to hold about a 15% screen value in the lightest areas.  I always thought it was to prevent stepping, but maybe for holding light-end detail as well?  Thank you for sharing your thoughts.

Great explanation with curve adjustments. 

BTW: Can you also successfully adjust casts to get similar results using an opacity-filtered and colorized hue/sat layer?

You can, but it's a lot easier with curves.