Sirnikoli

Why is Lapras Vday form such a rare spawn when nobody uses it in game?... People in the all chat say its one of the rarest forms.... Why??

Hey yall, I'm in Hoenn and I'm wondering what your opinions are for the best line up? I don't know this region, or the Pokemon that well so any info helps. I plan on getting a membership, but would like to know in advance so I can get them while I have it active.