Tengo preguntas sobre tus correciones.
Primero: puedo decir "para divertarme" o "por diversion" yo ambos son correctos en esto caso, verdad?
Segundo: Por qué debo sumar "se" a lado de "beneficiar"? Doesn't "beneficiar de entender" mean "to benefit from understanding" and "beneficiarse de entender" mean "to benefit him/her/it from understanding"? Por qué no es "beneficiarme de entender" tampoco?
Gracias multiplicado por un mil 
Hey Casey! how r u? enjoying the weekend? hope so..
anyways... it´s kinda hard to explain the reason of certain grammar issues... i ´ll do my best.! 
yeap, you can say both: PARA DIVERTIRME POR DIVERSION. both are correct. Here:
PARA QUE PINTAS? ( PINTO) PARA DIVERTIRME.
POR QUÉ PINTAS? ( PINTO) POR DIVERSIÓN.
Now the trickiest part: BENEFICIAR-BENEFICIARSE.
the fist one means, indeed, ¨ to benefit¨... the 2nd one i would translate as ¨ to benefit oneself¨ from sth... in your sentence i thought you were speaking in general about benefiting ¿? from understanding.. not specifically YOU.
In that case would be: ¨beneficiarme de entender¨ . ( to benefit (MYSELF) from sth.. )
well, i dont know if this cleared your doubts or confused you even more.. sorry in advance!!haahaha
see ya.. 