Yes, but, operations like, “Does this node have children or is it a leaf?” should not require reading the entire array. Or, how many children; get the first child. Traversing the tree in pre-order or post-order doesn’t just have less cache locality than a B tree (say), it involves sorting a vector of vectors and is at best N log N and O(N) extra space. Deleting a node requires a O(N) writes. Every little operation is massively less local and less efficient.

I stand by the lack of integrity that I got downvoted for pointing out! I’ll die on that hill.