I have learned how to gain more power.
I have learned two facts:
1. Text can be memorized, images are more difficult to memorize
2. There is a text that makes you happy when you hear it, such as good songs, interesting prayers, or stories...
From these two facts, the only conclusion which can be made is that person is supposed to memorize lots of songs he likes, lots of prayers he likes, lots of stories he likes.
Basically, if you have a song you like, you are supposed to memorize its whole text.
The song makes you happy, so it makes sense to memorize it and repeat on your own often.
I have memorized about 11 different songs and prayers so far.
I have to say, best way to do it is memorize them, then repeat each of them once a day, usually before sleep.
This creates a healthy brain, a productive brain, a safe brain.
I dont think there is any disadvantage with constantly memorizing things you like. Basically, you are filling your brain with things which make you happy.