This was among the very first animations, in the sense of multiple drawings. And I think I am right in this Gertie the dinosaur is the first animated creature. I believe she only appeared in two shorts, this and one earlier where the cartoon is the result of a winning bet. In both, Gertie appears with humans.
Now you have to have some context. In 1920, the theory of evolution was not widely accepted, and scientific data on dinosaurs was scanty. They had fossils, in fact Gertie is the "bringing to life" of one such fossil featured in the earlier short. Its one still displayed in the New York Natural History Museum.
People ordinary educated folks had no ideas about whether man and 'saur coexisted. These were mysterious bones, almost alien.
These films are important because they are early animation. But that's obvious. I submit that because film was so immensely powerful in those early days even more so than now that this implanted a notion that these two beings (us and them) could live together. Remember that photography was considered the technology of proof. If a picture or film of something could be shown, something was true. Animation and "real" film weren't as indistinguishable as we know them to be. But then in the last decade, computer animation routinely mixes with "real" shots and we believe what we see.
Since this, we've seen numerous movies where dinos and humans co-exist, and it hardly matters if it is set in the present as this and "Jurassic Park" are. Somehow, the deviant imagination holds it. Such is the power of film, that it helps weave stories that people need.
Ted's Evaluation -- 2 of 3: Has some interesting elements.