I have made this suggestion before and seen others post it as well. Crafters need this as a way to pool their cards just as we are allowed to pool our resources.
For example, my storm wizard does not need the 26 fire elf cards he has accumulated, but I could use them on my death wizard to craft something that I want for his house.
Not to mention it gets annoying to have your deck suddenly full of treasure cards then have to go sell them off in the bazaar when they would be more useful for one of my other wizards.
If we can trade with others how come not ourselves?
Arguement against:
More treasure cards would have to become level or PvP restricted since the use would increase (it's harder to find someone to trade your own cards to you than easily giving them to your lower level player).