Gas Giants are huge planets made up entirely of gases. They are uninhabitable, and often pose an extreme risk to anyone or anything entering them. Their size and relative lack of use lend them perfectly to hosting space stations around them.
Features
Unlike other planets, gas giants have no "world" within them; that is, they do not have a large plane with features on it as most other worlds do. They have very few usable resources, making them less useful to explore. As previously mentioned, they are far more useful when used to host space stations in their orbit. As for Surface, it's extremely difficult to build a base on a surface, you need tons of heaters from cold gas giants, you also need an anchor too. If gas giants have an almost safe temperature, you can have fewer amount of heaters at the time.