Here are two ideas for why PCs might go adventuring inside a simulspace. Please discuss.
One, an infomorph who resides inside the simulspace might only be accessible for interrogation by tracking them down and apprehending them inside the simulspace.
The second idea is not strictly supported by the canon, but what if someone built a back door into a system in a simulspace somewhere? For example, you go through a closet door in a particular house in the simulspace, and you come out into a Cognite VPN?
Of course, you could build a tiny habitat just big enough to hold the necessary computers to support a simulspace in which the infomorphs who populate the habitat live. That's an interesting idea for a setting.