$499 1.5 m RJ45 network cable
The AK-DL1 is a "digital audio reproduction" cable. Note the word digital. There are either 1s or 0s going down the cable. No analog signal of varying intensities or "nuances".
Another link - The Joy of Tech - Why premium cables cost so much.
Now of course this isn't to say that digital cables are perfect. A friend's office was being renovated and added to and so he decided to have them check all the cabling. Especially in his office as he was having random network issues with the connection to the server dropping. Well, it turns out that they got a high school kid into to setup the Ethernet cabling because head office was exceedingly cheap and they had to hide some expenses. Turns out the kid ran my friends network cable right over four fluorescent light ballasts. Cable was moved sideways and he's never had a problem since.
Update: It got slash dotted with a direct link to Denon's page. <guffaw> They're going to get slammed. And mocked.