If you have the dust there really is no downside, it's a no bRainer. The only real decision is are you gonna dust them or not afterwards for even more dust or keep them to play in wild. Now if you don't have the dust and you have to disenchant things in order to craft them.. then it's not really worth it. But if you do have the dust you're essentially putting it in a savings account & will get the dust back (and get to keep the cards).
i already had most of them in gold anyways but crafted the rest. I gotta add, I'm still mad they're taking ice lance and sylvanas out of standard. If anything needed to go it was the major aggro bs. that s&$@ ruins the game.