Source and Destination NAT Translations

Hi all, 

When to do source and destination NAT translation?
It uses for hiding source & destination IP address and deploys one-way direction, doesn't it? 

Refer configure source and destination NAT: https://www.juniper.net/documentation/en_US/junos/topics/example/nat-security-source-and-destination-nat-translation-configuring.html

Regards, 
Hoang Nguyen Huy