It;'s the whole point of their ad - taking the piuss out of the cutesy 'moving' emotional ads from other shops. Because they are right, it's about the food and the cost.
As well as the dead carrot there's the naff LIDL on the roof like the stupid ASDA advert, the snowman (waves to John Lewis) shut out in the snow, and the hint of a friendship between the girl and robin but she slams the window shut.