Honestly even that's only applicable to a few people. If you're really pushing progression, you can get far better value out of crafted gear than the 1:1 tradeoff that your allocation gets you. If you're way behind then you're better off just overgearing your way to the extra vit. So allocating vit for progression survivability is only a particularly good option for people right behind the hardcore crowd, who might not have reasonable access to crafted gear.
Also @ the people claiming it's better for general-purpose survivability... idk man. 30 vit translates to about 450 hp. So yeah dead dps do 0 dps and all, but if 450 hp is what's keeping you alive then there are other problems that should be addressed. If it works for you then cool, but be cautious about giving that out as general-purpose advice.