But you can also do so much more: these chips have lots of GPIO pins so you could control anything that an Arduino or another microcontroller can control such as relays, displays, temperature/humidity/proximity/etc. sensors, LED strips, motors, heaters, and so on. But the kicker is that with built in WiFi so you can natively get it online. A lot of smart lights now have these chips in them for example and you could make your own. Or your own internet connected green house with vents you can open/close and sensor readings for temperature and humidity in the air and the soil. Or an RC car you control from your phone. Or shades that open and close based on time of day. Or a garage door opener. Basically if you need a gadget you control over a network, these probably should be your first potential solution. They are low power and physically small compared to something like Raspberry Pi’s or other single board computers and more powerful than Arduinos.

I've mostly been looking at the ESP32, though (newer, also has bluetooth and 2 cores, and is lower power), and some of the ARM Cortex-M-based microcontrollers.

As the device has onboard WiFi I can poll a remote site to get data and display it, updating every few minutes. I use that to show the next departure-times at the tram-stop round the corner from my house.

Sure I could use an app, or even walk there and wait, but it's nice to know when to leave - especially in winter-time!

Alexa enabled switch to turn on / off a TV using the IR blaster

my boss used 3 of these this to build a smart sprinkler system for his house.