Loss covers more than just material things. Loss also covers family, friends, death of loved ones, etc. Loss can also be loss of health, loss of wealth, loss of family, etc. States of mind, as well, if we are feeling the loss of a pleasant state of mind then it can also be this. If there's a craving for a certain pleasurable state of mind and we feel that we've lost it, then it is very helpful to reflect on the impermanent nature of states of mind. So, loss does cover more than just material things. It also covers the loss of our body, ultimately, that's death.