I don't understand Kingdom Hearts in the bloody slightest

WARNING - THIS POST CONTAINS SPOILERS!

I never understood the appeal of the game Kingdom Hearts. I understand crossovers, and I understand highly artistic/non-mainstream projects, but I fail to grasp the connection (or necessity of creating a connection) between the two universes. Was this their track of thinking?:

- "I know! Let's amalgamate a cast of emo, sexually androgynous, magic-wielding teenagers with child-friendly, cartoony, animals that have no grounding in logical reality!"

- "I don't know what the fuck you're on, but we need to immediately order 500 pounds of it, and get busy! Promote this man!".

On second thought, I hope that no game designers think this way... Actually, I hope that no one thinks this way...