The scheme is not nearly as good as it used to be. DH and I had 3 city breaks (in 5 star hotels) back in the 2000s, entirely paid for by Clubcard vouchers.
We paid for the kids big Xmas presents entirely by Clubcard vouchers many years ago, they used to double the value at Xmas. It's no wonder they had to rein it back, it was jaw dropping. We have a Playmobil Hotel and a couple of other big sets, an expensive coffee machine and other smaller things. It was bonkers.
I bought a toaster recently with Nectar points, I'd been collecting points for so many years🙈
We still use the Clubcard vouchers for food treats at Christmas. M&S Sparks is just a waste of time, admittedly we don't do our main shop there, but I often do top up shops and it's the only decent clothes shop locally, so we buy a fair amount of kids clothes.