For Leon, the Impermanence Card wasn't of great importance—more of a collector's item. Regardless, it was an exceedingly precious legendary artifact, not something that could be casually discarded.
Besides, what Leon hated most was being deceived.
He couldn't tolerate being swindled, even for a single copper coin. He still vividly remembered being cheated out of five bucks as a child in the arcade, and later boycotting a restaurant he'd frequented for half a year over an unjustified one-yuan charge, emphasizing his vindictive tendencies.
I can give it, but you can't rob, fool, or steal it.
Leon was absolutely furious at the moment, but soon calmed down after some quick thinking.