I also prefer callbacks. Here are my reasons:

  - They are simple (fully transparent)
  - They are the simplest good enough solution for many problems
  - Cleaner code than new Promise().then().then().then().catch() clutter
  - Yes, I like nested indentations (good functions are short anyway)
  - They perform well

As a side note, I also prefer coffeescript, snake_case, CONSTANTS, and avoid using classes, prototypes, and this. I'm not very happy with the recent development of EcmaScript, too much complexity and unnecessary new concepts.