Camera Raw and JPGs in CS3

I have just upgraded to CS3 ( forced to as CS2 wont read my Canon 40D raw files ) I notice that you can now open and adjust JPGs in Adobe Camera Raw. My question is whether that is better than opening the JPG directly in Photoshop and adjusting it there. And if so, does that negate the advantages of shooting RAW over JPGs in the first place?

More infor in RAW than JPEGs = better pixs in my opinion

JPEGS + RAW converter in CS3 = better jpeg control

JPEG: 8 bits/channel of information in each pixel

RAW: Starts out at 12 bits per channel in each pixel; then is saved to a TIFF or PSD at 16 bits/channel per pixel, allowing far superior gradiations.

[Then, convert to 8 bits right before saving as a JPEG.]

Starting with Photoshop 9, err, CS2, Thomas Knoll changed the sharpening in the ACR 3 converter to sharpen only the luminosity channel, i.e. it works by converting from RGB to LAB color space, selects only the luminosity channel, and more aggressively sharpens just that, so that color noise is not sharpened.

I have just upgraded to CS3 ( forced to as CS2 wont read my Canon 40D raw files ) I notice that you can now open and adjust JPGs in Adobe Camera Raw. My question is whether that is better than opening the JPG directly in Photoshop and adjusting it there. And if so, does that negate the advantages of shooting RAW over JPGs in the first place?