My greatest generation and older boomer grandparents, parents, aunts and uncles always kept stashes of cash on-hand. They said if anything ever happened and your credit cards and later, debit cards didn't work, cash will get it done. Hence why I keep my stash available. Much like you with your aunt, when my grandparents passed on, I found more bags of coins and cash all over their home, garage, and yes buried in their backyard and at a storage locker. They left precise maps and information on where to find it. It was like hunting for buried treasure. Most older Black people grew up during Jim Crow, segregation, cross-burnings, the Klan and the civil rights movement. They never knew if or when they'd need to escape, so it stands to reason that they would have cash on-hand ready to go. I found absolutely nothing peculiar about Fani Willis keeping cash in her home or paying in cash.