TSubclassOf is a special template of UClass which only accepts specific subclasses of some base class. So it's still a UClass which is just a class specifier which you can spawn things from, but it does not have the variables or functions of the declared class. however, you can GetDefaultObject<T>() which is a master copy of the defined class object and contains the default variables which you can use before spawning that object.
官方文档：
https://wiki.unrealengine.com/Access_Functions_%26_Variables_From_a_TSubclassOf_Variable_in_C%2B%2B