Warm or cool light bulbs?

[Uriah D.]

What's your opinion on warm or cool lightbulbs? I sent new LED can light trim kits with warm color and warm color bulbs out to the house for install. House has Light French grey color walls. Guy installing them had to swap out trim kit for a halo style. He picks up cool color trim kits and all new cool bulbs because it "looks better" I have never installed anything but warm lights in flips before, not sure he is entirely wrong, but wanted to get others opinions.