By your logic a shitty no plot Mario games makes me care more about the character than I do about Kellanved from MBOTF. Sure Kellanved's influence on the world through the other characters' eyes and the explicit scenes involving him plotting are detailed and well thought out. But I didn't make him swing a sword 100000 times by clicking the B button. So I must not care about him.
You may feel as if you participated in the story by clicking the B button. But unless your actions created a difference in the outcome you didn't participate.
What extra knowledge do I gain about the characters' lives by playing that I can't get by watching? Does the game beam a plot point into my head that someone watching on youtube can't see? No? You mean there is not significant difference at all?
Oh brave new world.