This area is only useful for collecting Starflowers, which are used in Magic essence potions. During the quest A Fairy Tale Part II, the player must visit the Cosmic Plane to pick a Starflower to heal the fairy queen. After the quest, players can revisit the plane to collect more Starflowers for making Magic essence potions if they wish. When first arriving in the plane, there seem to be no flowers; however, they will start blooming after a minute or so, and players will be able to pick them.
The Cosmic Being doesn't have any apparent use, although it does ponder "universal mysteries" (such as "Where do flies go at night?"). The Cosmic Being has a number of different mysteries it ponders.
If the Fishing Trawler sinks, players can see part of the Cosmic Plane. (They are stored in the same area of memory.)
Using an Orb of oculus, players can see the Fishing Trawler ship to the west of the plane, and the entrance to the Cosmic altar to the east.
The Cosmic Plane can also be seen from the Cosmic Runecrafting altar with the naked eye or with the aid of the Orb of Oculus. It may be a coincidence that they both have the name 'Cosmic' in them hence both of them in a Cosmic realm.