Each area in Slime Rancher 2 will have a certain number of Treasure Pods for Beatrix to search for.
Slime Rancher 2 – All 18 Treasure Pods – Rainbow Fields (0.4.0)
Treasure Pods are in no way a priority for you to search for. The goodies they contain inside can also be farmed while searching for resources in the game.
With all games focusing on harvesting materials and exploring as the main theme, every resource counts.
If you look for these treasure capsules early on when you start Rainbow Island and have the extra materials, you will save a lot of time and effort in the long run.