They probably mean all the `using` macros, which can obscure where functions are coming from, and make it hard to get a grip on which functions are available in a given scope.
Having said that, Phoenix is nowhere near as 'magical' as rails.
Agreed. I found it confusing at first but once I understood that these things are laid out in web.ex it was quite easy to follow the chain to the original functions. I was also confused by where the helper functions came from, but when I realized that some of them are generated automatically from route definitions at complile time, things became clearer.
Having said that, Phoenix is nowhere near as 'magical' as rails.