Teresa Rivas, at Barron’s Tech Trader Daily, cites a note from UBS analysts Steven Milunovich and Peter Christiansen, below. The article is about Apple Watch, but it applies, more generally, to mobile devices. Bold emphasis is mine.
Voice messaging a “job to be done”: A year ago we suggested that voice could become an important aspect of the Watch. At WWDC Apple introduced voice messaging capability to Messages in iOS 8. With iOS 7 a message can be dictated, but it is sent and received as text. In iOS 8 a new microphone button is touched, a message recorded, and the screen swiped to send. When we visited with Tim Cook, he said that walking down streets in China one sees people speaking into their phones sending voice rather than text messages. Porting this capability to the watch makes sense as it is easier to send a voice message from a device already on the wrist than pulling out a phone. It also could aid penetration of China, which Cook said has a ways to go.”
Technology increasingly regional: In the US, adults hold the phone to their ear (or wireless equivalent) while kids prefer text over talk (ours refuse to answer the phone). But countries differ. An article in Motherboard says, “On any given block in Buenos Aires, you are likely to see someone speaking into their phone but not on it; talking to someone, but not necessarily with anyone. In reality, most people are perpetually sending voice memos to one another.” Argentinians are choosing voice memos over texting using less expensive WhatsApp rather than SMS.
Sending voice can be faster than texting when the content is long, complicated, or requires special emphasis. It’s also very useful when text-to-speech doesn’t work well, or at least doesn’t work well on the specific content the user aims to send. It’s also easier to do if the user’s hands are busy.