O(N) search is not fast. Hash tables and trees are O(1) or O(lg N) which are vastly faster than O(N). Imagine a database with billions of records. O(N) search

O(N) search is not fast. Hash tables and trees are O(1) or O(lg N) which are vastly faster than O(N). Imagine a database with billions of records. O(N) search on this database will absolutely murder performance.