If it had immersion features like special consoles for things, they would have a use. However, more than the cockpit and a few special consoles is really too much, we could have a bedroom and a kitchen but that would really only appeal to RP players.
There is however the issue of leaving and boarding your ship. Having an apparently seamless transisiton, maybe loading the instance when you cycle the airlock, so you can get out of your pilot seat, walk to the airlock and walk down the steps from your ship onto the landing pad and then around the various locations in the station, (market, contacts office, outfitting, shipyard etc) , maybe speak to a tech to fix/refuel/rearm your ship and so on. Walking in the cockpit would also have allowed us to get into the SRV before launch. That would give us much more immersion to show we are actual pilots and not some robot permanently built into a seat.
Walking on planets might be a start, but I personally would have like to have seen seamless transitions rather than black screen transitions like we do with the SRV. Walking in the ship should have been the first step toward that (excuse the pun), getting into the drivers seat of the SRV, THEN walking on planets. A transition can be loaded during an animated cut scene, such as getting into or out of the drivers seat of the SRV or cycling the airlock to leave or enter the ship, even getting in or out of the pilots seat in the cockpit could load a transition, no need to have space and ship interiors in the same instance.
Another way to have space and cockpit in the same instance would be to have lore built in. ie: "Pilots federation had deemed it illegal to get out of your pilot seat while the ship is moving, or in the vicinity of a station, unless ejecting from a ship that is too badly damaged to salvage." Therefore, you have to be in normal space and at a complete standstill to do it. You are already in an instance when you go into normal space away from a station, therefore space and ship interior can both be in the same instance. The server tracks all instances so, if anyone pops in and starts shooting, you can run back to your seat.
If the game appears to be seamless, from one part to another, there is more feeling of immersion.