No. A lot of people record voice messages, but they need to be in an environment providing enough privacy. But messengers emphasize text heavily in their UIs - again because of keyboards. Keyboard less touch devices are too novel an innovation compared to when instant messaging was cast into its final form.

> but they need to be in an environment providing enough privacy.

Yet another argument in favor of text.

Just an argument against audio and video. With a stylus instead of a keyboard you can still scribble amd draw naturally. That was my original example.