IF most of your images fall within sRGB, you’re wasting bits, and money on a wide gamut display. Karl’s point is, if you have 16.7 million defined colors in 8-bit, in sRGB, you have more precision seeing and editing those colors than the same data on a wide gamut display.
(1) Another point Karl apparent made was that Photoshop, computers and cables only communicated 8-bit. With the new unibody MacBook Pro's, Mini DisplayPort to DBI cable and CS4, will we be able to fully display the 16-bit colors from RAW files (as in being able to actually see that data on the WG display)?
Think of sRGB as a half inflated balloon with those 16.7 million colors on it. Now you blow up the balloon twice its size to represent Adobe RGB (1998). What happens to the space between those dots? They grow. The colorimetric distance between 122/123/156 and 122/124/156 in sRGB is closer than the distance of those values in Adobe RGB (1998).
(2) Merely interpolation and rounding issues.
Unless you funnel all the shots you take directly into sRGB, but rather shoot Raw and encode into a wider space, its pretty likely lots of your images will fall outside sRGB and being able to see that data to edit it is useful.
(3) Depending on the reply to (1); If yes, then what we will see on the display could be likened to a brilliant slide, while what KJKAHN above states will be how we preview prints at less than WG (similar to a scan or print from a slide)??