While it's true that the hashing isn't intrinsic to the mapping of key (bits) to value, hashing is what ensures that the tree stays balanced. You can absolutel

While it's true that the hashing isn't intrinsic to the mapping of key (bits) to value, hashing is what ensures that the tree stays balanced. You can absolutely use whatever bits you want, but patterns in the keys will open yourself up to potential loss of performance as the tree will get unnecessarily deep.