Both. We're due a very strong El Nino, with likely severe storms this winter. Power cuts, flooding and blocked roads are likely (see Devon & Cornwall today). Supermarkets may not be able to restock shelves in time so having a couple of days food in tins, and the freezer is common sense. UHT milk, an extra bag of pasta or rice.
We're under cyber attack pretty constantly from Russia, Iran and criminal gangs. They try daily to take down our financial systems. If they succeed, how will you buy food if your chip & pin or your phone don't work? So keep enough cash in the house for a week's groceries. Remember M&S being hacked, their order processing was down for three months. Imagine Tesco & Sainsbury being hit at the same time. That would cause shortages.
There is also a war in the middle east disrupting the supply of oil. If we have a cold winter in Europe, there may not be enough easily accessible fuel. Competition for heating gas would rise. The UK has very little storage. How will you keep warm if your heating doesn't work? Think about warm sweaters, battery lighting, how to keep children warm, fed & entertained.
I live rurally and I have the following:
2 litres UHT milk
tins of fish, meat, beans, tomatoes, fruit
25 ltres drinking water
An extra bag each of pasta, rice, couscous, coffee
basic toiletries, loo roll
wood & matches for my log burner
In the freezer, there's spag bol, chilli, sausages, chicken, veg.
I also have three water butts providing water to flush the loos.
A few years ago our power was down for 4 days. My elderly neighbours came to stay because they had no heat or light & no way to heat food.
It's about your family being able to cope for a few days if systems fail. That's all.