Well, ok, I have taken it a bit too far. Anything you can use or sell is technically an asset, even if it's more expensive to maintain than you would get on a sale (so even boats qualify).

But policy should never treat it as an asset. For policy, it should be a consumable good that only happens to take a very long time to consume.

The building depreciates and eventually is worth zilch unless you spend to keep its value (maintenance), but the land where the building stands is not a consumable.