Chinese characters are basically a language of pictures, which contain within them subtle relationships, images, and memories that cannot be captured by alphabetic language.
Imagine if all the movies in the world disappeared, and in their place were written summaries and descriptions of those movies. Imagine only being able to “experience” those movies through these written summaries, which would be but a mere shadow of the original.
How much information about the camerawork, director style, acting choices, etc. would be irrevocably lost?
The written Chinese language is basically an infinite combination of different types of movies. This is why Chinese translations of English works tend to be so much shorter than the original. Because you can pack so much more information into pictures than alphabetic language—hence the saying “a picture speaks a thousand words.”
To lose Chinese characters would be equivalent to losing thousands of years’ worth of movie-form information. Modern Chinese people would lose the connection to the wisdom and observations of their ancestors, which can still be so viscerally and directly experienced today because of the nature of pictures vs. words.