If you have a microcontroller to program, it can be an easy enough process to hook up a serial lead and perform the task. If however you have hundreds of microcontrollers on PCBs to program, ...
The various development boards such as the NodeMCU or Wemos D1 make working with the ESP8266 an absolute breeze. If they have a downside, it is that they are larger than the bare ESP2866, and of ...