Qwilfish has 95 base physical attack and 85 base speed, which is decent by in-game use standards. It can be useful in XY, where it can defeat NPCs with moves like revenge, aqua tail, poison jab, and waterfall. Qwilfish is the best spikes user in PU because it gets intimidate (to switch into physical attackers), taunt (to prevent opponents from using defog and their own hazards), and explosion to stop slower rapid spinners and defoggers. If you don't want to play through XY or play PU, then Qwilfish is useless.