Your Mother-in-law is wiser than you know. Fiat currencies come and go, but gold and silver stay valuable. If some catastrophe happens, and you and your family wake up to realise that you’ve all been transported to ancient Babylon, or the Persian Empire, or the Roman Republic, or Medieval England, or Ming Dynasty China, your credit cards and your bitcoin and your bank notes with Illuminati symbols on them will be useless. Gold and silver? Melt them down and sell them, you’ll immediately be able to trade with the locals.
It’s a smoky day in the postapocalypse. The fires never really stop, but…
A lot of Tumblr prompt fiction is unbearably twee to me. This is not. The author makes a point elegantly.