HELL YEAH!

No, not at all.
It at often times is misinterpreted as being a medium for children due to the history of how animation came to be. And especially with big names such as Disney and Pixar producing material where the main demographic is for children (although of course they're still for anyone). But it's just the big names that put this 'childish' label on animation, which people could I suppose come to the conclusion where they think the medium is underrated and not appreciated among all ages.

But now? It's very much appreciated and praised all over the world in all different kinds of styles. Animation is seen in video games, even live action films with a cgi animated animal or an exploding city for example. People love it. It is an art form that is acknowledged by many, acknowledged by the academy and all sorts of film festivals dedicated to animation. There are specific colleges dedicated to the study of this art form these days, where years ago such things did not exist. People enjoy animation, and the people who understand animation enjoy it even more than just the face value of it.

So underrated? Nooooo, not at all :P This is the ramblings of an animation student who knows the industry. A lot of people make a huge deal about this specific medium, they have the desire to use animation technique within their productions as it's not just restricted to 100% animated stories. Animation creates and enhances that which cannot be produced physically, and filmmakers are fully on board this train. NOT underrated xD

Hell no

Maybe at one point it was, but I don't think it is any more. I've noticed more people recognising its artistic value over time, and it's more widespread than ever.
Really, you see animation in some form or another just about everywhere you go.

Exactly What Zeppie Said !!!!