https://youtu.be/jVhlJNJopOQ

I just wanted to add this video to your comment because e-ink is so cool and this guy has a bunch of macro shots of the displays that are awesome and you can see the particles in the screen changing colors.

https://youtu.be/1qIHCUWAgh4

So cool!

This guy’s channel is so awesome, glad to see it posted here. He has all kinds of cool tools that he built in his lab like a scanning electron microscope. His videos on atomic force microscopes and laser lithography are really fascinating as well, he is really great at explaining the concepts too, definitely recommend!

Well 5ghz requires more power, has less range, and needs its own antenna so for microcontrollers this makes it pretty pointless for devices that need range and low bandwidth for sending sensor updates, especially those that are battery powered. 5ghz can also have its own issues in cities if you have a lot of use of the DFS bands as well as being worse at traversing reinforced concrete.

Also, a 2.4ghz radio can also sometimes support other things like zigbee, BT, and BLE which can be used for other functions.

For what it’s worth, I have probably 50 WiFi devices and the majority of them are 2.4ghz sensors or switches and other low bandwidth tasks and I don’t have any issues, even when living in an apartment complex. If you are having issues you might need different hardware or more access points or something.

Anyway, all that to say that 2.4ghz definitely still has a lot of utility today.