Recently, when skimming the various teambuilding articles/threads on Smogon, I see many references to Quagsire. Why Quagsire? He is repeatedly referred to as a great wall, and I guess Unaware is usefull to break past setup sweepers/stallers. But he still has subpar stats and a massive Grass weakness, which is bad with all the Breloom, Mega Venusaur, Bullet Seed Mega Heracross, etc. in the tier. I also see moveset suggestions mentioning Quagsire, such as Mega Metagross running Grass Knot in order to crush him. Is Quagsire really that common, and if so why?
P.S. It''s not just Smogon where I see this, I've also seen it here and Serebii.