The explorative character of the MMA/Wolfram language is probably mostly due to the "REPL on stereoids". IPython provides a similar attempt but is "traditional"

The explorative character of the MMA/Wolfram language is probably mostly due to the "REPL on stereoids". IPython provides a similar attempt but is "traditional" OOP (with explorable documentation and members/methods). Therefore, I am not that sure about the unique selling point of Mathematica. From my POV it is the pure size of the library and thus power of expression evaluation, like finding the algebraic solution to a complicated integral.