Sarah - I do take your point about the differences for toddlers in terms of perspective and experience.
But we have to remember, that is all they know, so for them, it's their reality, they have nothing to compare it with.
As adults, we have the physical and mental capacity to experience, and understand, the difference between our world and theirs, but that's because we are adults.
Little ones don't think like adults, they simply experience, and accept the world as it is, so we need to beware of thinking that they see the world in a negative way, compared to our experience.
They don't. They see what they see, and adapt as that view changes until adulthood, when they can think about it, like we do.
So although we need to be aware of some basic differences based on simply size difference, we should not worry constantly that the world is a huge and frightening place for children.
If they are with supportive and loving parents, it's just the world where they are.