>>23037238>Pachirisu is Se Jun's favouriteStop this. For real.
In a format with limited options just like '14 was. The chance that the extremely obscure Nichemons would appear is higher.
Se Jun knew that almost everyone would be prepared to both Amoonguss (Spore, Rage Powder) and Rotom-W, he need to use just one slot that could be able to redirect the attacks and also stop Electric Attacks since he used both Gyarados and Talonflame.
Pachirisu was that Nichemon, with Follow Me, its redirect bypassed everything that Rage Powder can't. With Volt Absorb, foes weren't willing to spam Single Target Electric Attacks. Also, just like every electric Rodent, it had an un-Tauntable Thunder Wave in Nuzzle, and offensive presence without investment in the form of Super Fang.
Using Pachirisu wasn't using a shitmon for the sake of it, it was a good read and a good call for the Metagame of that year. It was a high risk choice, but it payoff in the end.