The use of animation in movies is one of the greatest accomplishments in the entertainment industry.  It opened up many lanes for artists to jump into the movie industry. Animation also spoke and included another audience into film viewing. That audience is known as children, most of the movies made beforehand are more aimed towards adults. The special effects in Citizen Kane are top-notch. The use of the deep focus shot to focus in on the picture so it could turn into moving objects was great.  Snow White and the Seven Dwarves was the catalyst for many amazing animated movies that followed. Hercules, Aladdin, the Lion King, Nightmare Before Christmas, Toy Story, and many more. Even though Japan had animation in 1907, this was the first major animation movie that setup many more.
I definitely agree that animation is one of the greatest accomplishments of the entertainment industry, considering now twice or even more people were attending these films. Snow White and The Seven Dwarves definitely set a great precedent because now whatever came after it would have to be as good or better than it.