Volbeat. Another Bug. *sighs* Why are there so many Bug Pokémon? Ah well. Each one of these seems to have some unique trait. Volbeat has two: Tail Glow and Prankster. Tail Glow used to be Volbeat's signature move, and is basically just Nasty Plot with a more stupid name. However, with the upgrade of Tail Glow in this generation (+3 instead of +2 SpAtk boost), it makes Volbeat slightly less bad. Also this generation, Volbeat got Prankster through the Dream World, and +1 priority to non-attacking moves is a great addition for anything.
However, that's not to say that Volbeat has his faults. Actually, he has quite a few. For starters, it's been cursed with a Bug typing. Fire, Flying, and Rock destroys it, as does Stealth Rock. Also, Volbeat has some pretty bad stats. 65/55/75 defenses are ridiculous, and the attacking stats are a joke. While 73 Atk is bad, 47 SpAtk is just awful. Even with Tail Glow, you can't do anything. Finally, it's signature move was also given to Manaphy, who can utilize it better. Overall, Volbeat is just... bad.
So, what use does it have? Volbeat can perform a useful role: priority Baton Passing. It can come in on an asleep Pokémon, Tail Glow on the switch, and Baton Pass to something that doesn't have a 47 SpAtk base stat. Think of it as a wannabe Quiver Passer. Overall, Volbeat is awful, but it still has it's niche.