I believe that linguistics is one of the most important uses of language. Think about it, you learn to speak before you write. Also the way you speak differs from the way you write. Most people, myself included, tend to speak in a very informal manner unless in a formal setting. However, most people write in a more formal tone almost all the time. Texting and personal emails don’t count.
Linguistics also vary by region. For example, where I am from, the state of Mississippi, people tend to talk slow and draw out their words. Vowels tend to be flatter and words kind of just slide together with no crisp ending to words. This contrasts where one of my roommates is from, Connecticut. He speaks very fast and crisply. And at first it was almost hard for us to understand each other unless we spoke very deliberately. All in all I believe that linguistics is more deeply rooted in the human language than writing and the technicalities of it.