The Iliad doesn't pull any punches in its portrayal of mortality. Not only is death in battle depicted as extremely painful and gruesome, there isn't any rosy afterlife to look forward to. In fact, in Book 20, Hades, god of the underworld, is terrified that Poseidon will crack open a hole in the earth, and then everyone will see how gross it is down there. Most of the time, though, death is described simply as a cloud of darkness that comes down over one's eyes. Because nobody looks forward to anything after death, they all try to get on with their lives – which usually means having as much fun and winning as much glory as possible. None of this applies to the gods, of course, who are immortal. They pretty much party all the time.
Even though Achilleus tells his mother he wishes he hadn't been born, the Iliad as a whole thinks life is worth living.
The frivolous nature of the gods' existence suggests that mortality has its benefits.