Wechat
I have read most of the comments made on this thread. I haven't posted in a long time but felt compelled since I have lived in china for the past 8 years.
It is correct it is easier for Chinese to send a voice message as opposed to type out a long form message. They have something called pinyin that is a very intuitive and fast way of typing Chinese characters, but it is still a bit of a chore. Quick voice messages are much more efficient.
I am sure what Tim cook witnessed and described was Chinese people using an app called wechat. It is the absolute universal go to social media app that everyone in china is using right now. It is excellent. If you're not on wechat right now in china and other parts of Asia, you're not connected. Of course, you can send traditional text messages, photos, videos, etc. like any app that's been around for years, but everyone overwhelmingly prefers the quick walkie talkie like voice chat feature. I initially was resistant to it because I like to respond when I want, and via text message because less emotion is conveyed. However, as time has gone on, I find myself sending short audio messages more and more. It's just so convenient, and intent never gets lost.
I agree it is more beneficial for the Chinese to communicate this way because of their written language but i find myself more and more communicating with my expat friends in this fashion every day. Even my family back home in America all have wechat and that is now our preferred method of communication.
Maybe just for fun give it a download and play around with it to see what 1/4 of the world population is doing right now. It's nothing that hasn't been done before in other apps but it is packaged and implemented so well.
It's easy to knock quick voice messaging. I know I did. But now, I feel I can't live without it.
I live in guangzhou. There is full service on the subway lines at all times.