Honestly, a green bud can technically have more Cannabinoids than one that is purple or black or whatever other colors that may show up, but feeding for cold climates would likely rectify that where they'd have the same. For me it's not really a choice anyway, as my outdoor here in Michigan is going to see cold weather every time. Might look super pretty, and have bag appeal, but at the end of the day, it's just the plant reacting to stimuli really. Just like in the North, when temps start getting colder, and the Trees start turning beautiful colors before the leaf matter falls off.
Now, one thing about cold, is that, even though the plant changes, and colors can appear, I've also seen clones of the same plant grown in a warm tent VS being outside in the cold, and though the outside was more colorful, the resin production seems to have been upped too. Apparently resin is a lot like weather proofing for a Cannabis plant, which, kind of makes sense, as it's water proof, and can block cold air from penetrating to where potential seeds might be forming. Even if there are no seeds. I first saw this myself when my in law got clones of Detroit Lemonade a few years ago. The indoor clones were not EVER cold, and didn't get any colors or anything like that, and though they were sticky, they never quite got to that level that the ones outside did. The outside ones were ridiculous with resin production, and were just covered in it. I didn't take any scientific measurements or something like that, but just from looking at them, you could see the differences pretty clearly.
I will say, that I've seen plenty of colored plants that weren't cold either. LED lights seems to be able to bring those out at times too. My experience on that end though, is pretty limited, so, your mileage may vary. I simply don't have that level of indoor tent experience to say it's a fact.
