King Sombra hidden somthing that could destory him dosn't make sense to me. But what if he hidden it to protect it from himself until somone come by claim the throne.

I have this theory that he was process by a demon that spread hatred and fear, but was absorb by Sombra to save the cystal empire but slowly but surely the demon would control him so he decided to hide the cystal heart somewhere so the demon won't get to it. He decided erase the cystal ponies memory so when demon that process Sombra would be weaker and also would have a hard time finding the Cystal Heart.

Do you agree with my theory?