The Supreme Court case Texas vs. Johnson established the freedom of speech can apply to more than just words. For example, in this case, the Supreme Court ruled that the burning of the American flag is protected under the first amendment of the US Constitution.
It is important that nonverbal elements of freedom of speech are protected, as it allows citizens to voice their concerns with societal issues or government actions in a variety of ways. Along with this, if the government starts to restrict some freedom of speech, it could continue to limit other forms of free speech until citizens rights are severely restricted.