Per jan Sonja's design, toki pona is not an international aux language. It has few of the goals or design criteria of Esperanto.
Toki pona is a game, it is a innovative idea for treating depression, it is an extended experiment in learning what is the fewest root words one needs to communicate a broad set of ideas, it is a way of inducing a sense of simplicity in thought and speech. It is also remarkably easy to learn, albeit at the cost of making some things--certain vocab categories and certain grammatical constructions-- very difficult.
These goals are a long way from world peace, being easy for indo european speakers, or being useful as a neutral intermediate 2nd language for discussion between two groups of people who don't want to speak the national lingua franca of the moment.