I don't think this is the "Death of Typography", but rather just somebody's particular use case. I would personally never send a voice message, as I believe that I can type just as fast, and express myself more clearly in written form than in spoken.
I don't think type is going to be dead anytime soon or ever. There are 2 things I would point out: 1) For conversations, it's convenient for users to send a voice message rather than a text. We speak faster than we can type, and it comes more naturally. 2) There is a large population of people who aren't "digital natives" that find it easier to speak rather than having to learn how to type.