In Tsukaeru Cloud every server has local IP address, but assigning global IP is arbitrary. Because server with only local IP address does not have access to the Internet, in case you need to connect to outside world (installing software with yum, updates, etc.), please assign a public IP address.
You can easily delete assigned global IP address when it is not needed anymore.
For security reasons, it is recommended to first set firewall rules to limit unwanted access, before assigning global IP address.