Well, saying that flatMap is “more powerful” than map still kinda makes sense to me, since flatMap is like an advanced map that also knows how to flatten. With flatMap we can build monads and with map we can only build functors. What you are saying is a bit weird though — how can a function be more or less “powerful”? A function that maps an integer to another integer is not inferior in any sense to a function that maps an integer to a list of integers… But we’re talking about subjective stuff anyways (there’s no such thing as “level of power” when talking about either functions or category theory constructs) so let’s stop here. :) Glad you liked the post!