I've wanted something akin to this for D&D played online. I could activate my "elf NPC" mode and have an elf avatar redub what I'm saying in a distinct voice, inflections to match gender, etc. It's a very niche usecase and I definitely don't mind doing a mild voice and having everyone fill in with their imagination. But it would be cool if implemented well.

Problem is, once this exists, it's a misinformation nightmare for the rest of the world.