Exactly! i need to change my transmission fluid and the car has to be on a level surface and an in-ground shelter fills the bill!With a floor safe you can easily do your own engine oil drains.
When they installed our in-garage shelter, it was put in one of our garage bays and I didn't know it but they must have been close to the sewage drain because every time the toilet is flushed the water can be heard in the shelter-almost as if they barely missed the drain when digging!