Why not use hashing/hash tables for everything?

Question

In computer science, it is said that the insert, delete and searching operations for hash tables have a complexity of O(1), which is the best. So, I was wondering, why do we

Answer 1

1. Hash Tables are not sorted (map)
2. Hash Tables are not best for head/tail insert (link list/deque)
3. Hash Tables have overhead to support searching (vector/array)