I saw it as a re-telling of his upbringing. It was a gut reaction to being around a stack of cash and jewels. However, given the amount of time they've been living in the Walking Dead universe, I found it odd that he would suddenly exhibit such behavior. The darts thing made sense, but Daryl is a survivor and should have been more practical at that point than to lug a pocketbook around with him full of trinkets he knows are useless in his world.