So who the hell builds Moonflair Spellblade?

If you guys don't know what Moonflair Spellblade is, I don't blame you. It's a Twisted Treeline item that gives you:

+50 Armor +50 MR +50 AP +35% Tenacity

My question is: What champions are MFSB designed around? It doesn't do much damage for full AP mages, and isn't really tanky enough for tanks (atleast with my observations.)

So who in particular builds this item, if anyone at all? I want to get into TT before it inevitably gets shut down, so any info would be nice.