Are Open Addressing in Hash Tables only useful for searching ? How do the elements get into the HashTable in the very first place?

问题

From Wikipedia link on Open Addressing :

Open addressing, or closed hashing, is a method of collision resolution in hash tables. With this method a hash collision is resolved by probing, or searching through alternate locations in the array (the probe sequence) until either the target record is found, or an unused array slot is found, which indicates that there is no such key in the table.1 .

I have two questions on this .

1. What is the intuition for using the fancy term open addressing and closed hashing?
2. Is this open addressing method useful only for searching but also for insertion ?

来源：https://stackoverflow.com/questions/12005405/are-open-addressing-in-hash-tables-only-useful-for-searching-how-do-the-elemen