The Mistborn Powers of Harmony

from ten soon i find this a little confusing why would ten soon know that this is a possibility and think that someone with mistborn powers would know more or be capable of more than harmony he says harmony doesn't understand how it would be possible. if the shards kind of like forget what being a physical body is like and then you give a lot of the power of a god to someone who is still definitely in a physical body it like allows them a new perspective. maybe the vessel and shard doesn't happen too much of a stretch toomuch of a stretch it doesn't make any sense at all it wouldn't make anysense except ten soon is saying that it will make makes no sense but