Voice-controlled features have gotten much better over the years, but they're still not perfect. This can actually work in your favour, if you have problems with mumbling or public speaking.
As reddit user Stdruler points out, voice features force you to speak aloud what you'd normally type. If you use an Android or iOS device, you have a litany of voice commands available to work into your daily routine, or you can download apps to transcribe everything you need to write.
Even if you're not inclined to use these features as part of your normal work routine, integrating them can help you exercise your vocal chords and learn how to pronounce words and speak more clearly. It may even help you get over your fear of public speaking.