Cream is a color-and-texture word name: soft, pale, rich. It works primarily as a coat-color descriptor promoted to proper name. The dog is cream-colored, so the dog is Cream. Simple, descriptive, and the word itself has a warm, comfortable quality as a sound.
The Coat-Color Naming Tradition
Color names on pets are practical and ancient. Cream sits at the luxury end: not just white, but warm-white, rich-white. It works especially well on Golden Retrievers, Yellow Labs, and Great Pyrenees where the coat color genuinely matches.
The Pop Culture Layer
Eric Clapton's band Cream (1966-68) gives the name a rock history association for owners of a certain generation. The phrase "cream of the crop" adds a best-in-class connotation that works quietly in the name's favor.
The Counter-Reading: Very Literal
Cream is essentially a physical description. It works beautifully on the right dog and reads oddly on one that isn't cream-colored. The name also has no personality signal at all: it tells you what the dog looks like, not who the dog is.