ESP’s are great to give your sensors the possibility to extract the sensor data, because of the on-board WIFI chip, which can connect to your network.
Imagine you have multiple sensors, and you would like to access the measured data and show it in Home Assistant. You can either spin up a web server on your ESP and pull the data or send data from your ESP to your Home Assistant.
The advantage of the push strategy is power saving through deep sleep mode of ESP, which will be explained later.
In my case the + and - pin label was incorrect and I had to swap them. So that the orange wire is attached to + (and not -).