I personally wouldn't even call it a "pedigree" if it just had the name and color on it, but that's just me.
Keeping track of colors is done, I always assumed, so you can see the "color history" of the chin. I feel it can also tell you something about the breeder. For example, one of my friends just purchased a chin from a "breeder" where for the last 3 generations, this breeder bred violet x violet = violet. In case the problem isn't clear, let me explain -- those chins would have to be show-stopping GSC violets for someone to breed violets x violets, as most people would breed violets to standard violet carriers as violets can typically use some improvement. So... in that case, those pairings tell me that breeder was more concerned about churning out more violets than they were concerned about churning out quality.
Also, another reason color is kept track of is because some colors are recessive. I have a standard chin here... he must have ebony SOMEWHERE in his lines (though there's no ebs on his pedigree) because when we bred him several times... we'd get ebonies or some dirty-bellied standards. In the case of someone wanting to breed pure standards... it would be worth noting that this male is clearly an eb carrier. Which a pedigree should divulge, if the person did know he was an eb carrier.
I have seen a breeder keep pedigrees just for color. Same (bad) breeder as mentioned above (with the violets)... different friend bought two standard females from them. The pedigrees read: standard, standard, standard, standard, standard, standard, standard... and so on. Now, I don't know how that's a helpful "pedigree" at all, because for all anyone knows, those chins could be inbred, the two standard she has could be related somehow, no one knows. For a pedigree like that... I would say that was someone who wanted to breed chins, didn't have chins of quality (so, no pedigrees), heard that good chins have pedigrees, and decided to "make up" pedigrees. Cause really, who can't fake a pedigree when it's only colors?
But ignoring bad breeders... I've actually noticed that I have more pedigrees that have a ton of information like ranch brand, animal number, show placings... but not color. So, I wouldn't think the average breeder would keep a pedigree just for the purpose of keeping track of color.
Even for pet sales, I still provide a full pedigree if someone's buying a pedigreed chin from here. Maybe they don't want to breed now, but maybe in the future they might, and they'd have the full pedigree then. But, I've seen several breeders that will give very limited pedigree if it's a pet sale... I suppose they don't feel the need to mess with writing out a whole pedigree when the person buying the chin doesn't care about the pedigree and doesn't intend to breed the chin.
That said, I bought a chin at Nationals a few years ago from one of the well known ranches (now out of business). The pedigree listed the number of the chin (A20), the number of her parents, and that's it. If I didn't know which ranch she came from (which I do know from her show card), it wasn't on the pedigree. Neither were the colors of either parent. And that was from a well known breeder, who I would have expected "more" from. When this person was handing me her pedigree, he was flipping through several pedigrees, and they all looked just as barren when it came to the amount of information being on them. On the other hand, I've gotten pedigrees from other well known ranchers that includes everything down to great great grandparents. Maybe not color on all of em (but def. colors on the ones that rancher bred), but information on ranch brand and chin number. So, some detailed, some not so much.
So, I think it just depends on the individual breeder as to how in-depth the pedigree is. For me, I want the most info possible, and if I have the info, I will put it down on the pedigree.
Back to those two standards.... my friend isn't breeding them, they're just pets, but with those "pedigrees" I wouldn't be comfortable breeding them even if they did look like stellar examples of chins. I feel there's just not enough information, at least for me.