Mono No Aware has been said to describe a sentiment of pathos relating to the fleeting nature of our relative world. In addition to a feeling of lifes fragility, mono no aware relates to seeing beauty in this fragile,impermanent nature, and even grasping that without impermanence, genuine beauty cannot exist.
Experiencing the fragility of life affirms the worth of living. Beauty fades as quickly as it is experienced and thus it lives forever.