Ryoshi78 написал I'm just wondering what could be a good use case for something like this or when is recommended to set it up differently?
I'm not sure I understand your question correctly. It always depends on what you need, but in general if your skeletons are "logically" independent and animate separately (not in sync, not the same animation), you can use separate skeletons. Note that you could also use two independent animation tracks to animate e.g. a gun independently from the main body. If they are dependent and should animate in-sync, then it would make things more difficult when they are separated, so don't split them in this case. This is just a very rough rule of thumb though, and you might find exceptions here.
When working with multiple people on the same project, please always be sure to discuss such matters with all your colleagues (artists, animators and programmers), they might consider different aspects that you might overlook.
