You can trade them for Provisioner Tokens at Rend Scorchmaul in the Wizard’s Tower who does not have a daily limit. This would have been an unlimited supply of tokens for roughly 20 silver a pop (see below) and people already know that they will need 300 tokens per piece of legendary armor.

But the Price for Quartz Crystals does not appear to have exploded, since ArenaNet was quick enough to fix it. Or maybe it’s true and the exploit did not even consume the stacks and you could get unlimited amounts of Charged Crystals == Provisioner Tokens for free while it lasted.

I can craft a bit and sell it

Probably not, since ArenaNet crashed the market for (crafted) exotic gear with the addition of a new WvW vendor who sells stat selectable exotics for very little coin and honor. If I were mean, I could say they did this to make people buy PoF and HoT so they can also pick stat combinations from these expansions. Anyway, crafting is now officially dead.