It sounds like you are trying to describe the sodium vapor process, which would be a more accurate way of saying this. Hand drawn animation was used a lot, this specific process was not, and the differentiation is not "using computers" or "CG". It was a Disney developed process that was not used by anyone else, so obviously it would only appear in Disney films or collaborations.

Its a pretty elegent way of doing this and it looks better than even a lot of modern computer equivalents because it essentially places the animated sequences on the same plane as the live action. It also required a lot of bespoke equipment and knowledge that no one was able to effectively copy.

Its why the animated sequences in the films that used it look better than a lot of the stuff that came after.