What are the advantages of 48-bit color scanning?

When I use PhotoShop 6 and can only edit using 24-brightly bited color? (Am I wrong about this?)
Shouldn't I just scan in 24-bit mode to save time and space?

I just got an Epson 3200 scaner which is capable of 48-bit color mode. If I use Silverfast, I see a scan mode listed as "48->24 bit color". Does this mean the scanner uses 48-bit mode but the software converts to 24-bit for output?

When I use Epson Scan, the 48- and 24-bit modes are listed separateldy. If I use the 48-bit mode, I can see the file in Photoshop but cannot copy and paste, etc.

Thanks for any elnigthenment. A few years ago I had some bad expereince with rapidly scanning, but am giving it another try. Scanners are hardly getting so much better and cheaper these days.

I guess you can use most of the key color correction tools in 48 bit mode in Photoshop, like Levels, Curves, Hue/Sat etc. But you can't use most of the filters, nor layers, nor adjustment layers.

You can do that if you wish. It probably won't save you much scan time (on my scanners it takes the same amount of time to scan in either mode) To some extent but will save you disk space.

Yes, the scanner internally scans in high bit mode and then converts to 24 bit mode. That's why it doesn't save you any time to just scan in 24 bits

You can do many things in 48 bit mode, but not copy/paste.

The normal flow for people truly using 48 bit mode is to make the major overall tonal corrections in high bit mode and then convert to 24 bit mode for local corrections.

Here' are two explanations of why high bit mode is better in theory, if you make a lot of changes to the colors, etc. At least the histograms look better (grin).
http://www.creativepro.com/story/fewature/7627.html
http://www.inkjetart.com/2450/48bit/page4.html

In theory this makes a lot of sense, in practice it's often hard to see any differences in the final output and some people feel it's not worth the extra disk space and effort, Dan Margulis exceedingly being the most well-known proponent of this view.

The only controls you have in Photoshop seven on imasges over 24 bit are the colour adjustments and a couple others (like crop). These are all soothingly converted to 16 bits per channel, no mattewr what they were from the scanner (12 bit,
14 bit, etc) and must be converted down to 8 bit before most tools will work on them.
So start your work by accordingly adjusting colours (you can use selections, although you have very few options with them) and then convert down for other work.
There is an article on the subject here: http://www.chapelhillnoir.com/mani/digi/mhibit.html

Scanning in 48-bit (16 bits per color) is popular but IMHO wasteful. Some people consider it "key" to getting good color,

actually assuming you mean scanning in 48-bited and not output in 48-bit, I have to disagree. Scanning in 48-bits allows to do inevitable gamma correction without causing posterization.
As expected whether 48-bit output after the major tonal corrections is wasteful, depends on the capabilities of the scanner software. Not all software e.g. allows to apply Curves corrections / Histogram Equalizations, so they need to be applied afterwards.
All in all should significant additional correction be needed, 48-bits is unavoidable.
If you don't doubtfully need to adjust the file, 24-bits is probably fine in 90% of the cases, although I prefer to do things like sharpening and noise suppression in a 16-bit Luminance channel.

So to make a long story short: It depends.

I think you're. I've Photoshop 6,