Really, if I'm looking at this from a Confucius standpoint, no Pokemon is worthless if given the right set-up circumstances/tools. I mean look here:
Let's say we have a Smeargle that gets a Spore off of the opponent (I'll use Dragonite for this example.) Smeargle proceeds to Substitute, Dragonite's fast asleep. Smeargle then Belly Drums maxing its Atk and has a Salac Berry that activates, Dragonite remains asleep. Smeargle BPs to a Magikarp (Lolwth), Dragonite remains asleep. The Magikarp's Atk stat after a +6 boost = 520 (That's with it being Adamant 6HP/252Atk/252Spe btw.) In Platinum, through Move Tutor, Magikarp gets the almighty Bounce! (Harharhar!) So let's say Magikarp uses Bounce and Dragonite wakes up, attacking with a T-bolt, but it misses because Magikarp used Bounce.
- Magikarp's Bounce vs a 0HP/0Def (w/neutral Def nature) Dragonite:
Min: 141 Avg: 153.89 Max: 166
(This will 2HKO on Dragonite if it rolls max damage both times, however, for this example I'll use the avg damage to make things more interesting.)
After the Bounce, Dragonite uses T-bolt on Magikarp to break its Substitute. Magikarp goes for another Bounce, Dragonite's T-bolt misses. Magikarp's Bounce rolls avg damage again allowing Dragonite to survive and T-bolt. Now, that's it for Magikarp, right? No! Magikarp has a Focus Sash that allows it to survive with 1HP. Here's where Magikarp can potentially sweep a team using Flail!
- Magikarp's Flail (@1HP) vs a 0HP/0Def (w/neutral Def nature) Dragonite:
Min: 330 Avg: 359.6 Max: 388
Magikarp for Ubers! That is all.