Hi,
I have the red and black inky pHAT sitting on my desk showing the weather station.
As it is three colours, it really does take about 15 seconds to refresh.
Mine is set to refresh every 15 minutes, and the display flickers whilst doing so.
I imagine watching this continually flicker for 15 out of every 30 seconds would become tiresome very quickly.
The black and white one has a quicker refresh rate, at a few seconds.
Personally, if I were showing rapidly changing data I would use LEDs.
The Four Letter pHAT has a nice CPU example that is constantly refreshing.
I guess it depends on the amount of data to display, the aesthetic you are looking for etc.
Also, The inky pHAT story.
Cheers,
Simon.