Before the time of text messages, there was something more irritating and disrespectful being done while in public or even during casual conversation. Even people only a few years younger than me may not have experienced the horror that PTT (Push to Talk) phones caused; I personally experienced it in middle and high school. For those who don't know what PTT is, think it as a walkie talkie that actually work long distances; as a child, I never received (or couldn't afford) walkie talkies that actually worked consistently.
Why were these PTT phones so aggravating? I'm sure you've been in a conversation where the other person starts texting another person. Well, imagine that and their text ringtone is an obnoxious beep and the text message is read extremely loudly in incomprehensible horrendous quality. And I remember hearing that Nextel beep all across school grounds; it haunts in me in my dreams. It shocked me that no one saw how the entire experience was unpleasant (even in the commercials).
With higher sound quality and wider service availability, the PTT service seems more feasible. But it would only work effectively in certain situations (e.g. when you are alone or have a headset on). And now it's available for group where before it was only between two people! I started using Voxer yesterday and I must say it brings back the days where I desperately desired a walkie talkie (though I wouldn't know who I would have talked to). It probably will be a novelty in my case since majority of my friends are no on it but I can find it useful for times where a phone call takes too much commitment but texting is too slow/dangerous.
This would be excellent for head-mounted devices like Google Glass. It would be a good way to avoid the current inconstancies of voice-to-text (though, leaving the transcription would be useful especially in various situations). This way would avoid having the robotic text-to-voice conversion too, not to mention the loss of tone.
The concept of voice commands/search (with the help of Moto X in the near future) will become more natural. I wouldn't be surprised if something similar to Voxer becomes the standard of messaging with texting being the primary input (unlike in Voxer) and with transcriptions.