I like the puzzle-solving aspect of it - like doing Sudoku, or Alphaguess - but I don't particularly have the time in my life right now to use AoC to learn a new language. (The last time was approximately 6 years ago, when I was learning Elixir - which was also for work. It was also when my child was young enough that I had spare time after her bedtime, but not so young that she didn't sleep through teh night.)