It's one of the few products I look at with awe and which makes me feel good about the tech industry.
I managed to build a WiFi temperature sensor (which can be substituted with any analog sensor) which streams its data to a web platform (I also built), encrypted over HTTPS (with CA certificate verification), using a $10 Raspberry PI Pico W; built in a single weekend. I can connect it to my phone's WiFi hotspot from anywhere and stream data to my web platform where it displays a realtime chart. $10.