TWT - Target Wait Time promises to be another boon to the Wi-Fi marketplace, by extending client battery life and reducing network congestion.
Here is one article from Celeno that makes these claims:
From a practical standpoint, I have seen several wireless features that promised great things that never really panned out. Some of which have eventually been eliminated, like Greenfield Support.
I have also seen a seemingly endless chain of Power Saving algorithms, both industry wide and within my past employer. Often times, reality has stepped in to disprove the efficacy of the power save mechanism. What seems to work for one device, totally fails for another or only works in a particular WLAN and RF environment.
I expect that TWT will provide some improvements in the IoT world, but not much for Wi-Fi in general. We will have to wait and see. I'll give it two years to prove its worth..