data structures – Binary Tree as 2D array with variable length raws

Usually we use the tree data structure when we care about time complexity for ins/del/…

-In this special case problem, space saving is mandatory too that is 2 pointers for each node is unaffordable; actual data are in leaves so infact even the internal nodes are considered overhead

-So, I thought of storing it as a 2D array with variable row size, we can assume the tree is almost always full complete power of 2, something like

R[0]= N leaf nodes

R[1]= N/2 level-1 nodes

R[2]= N/4 nodes

..
..

R[logN]= root

-I can derive the formulas for del/ins/… as the tree is easily mind-vewable from this presentation, without any pointers at all.

-Now, did I miss something???
-Is there any flaw in this?
-I’m checking for brainstorming or some opinions.