The reason this ad is such a banger is that, before anyone wrote a word, Ocado commissioned research that found nearly two thirds of their customers already do "high-low" shopping AKA splurging on hero ingredients, saving on the basics.
And this ad is so firmly rooted in understanding how their customers think and shop that the copy doesn't even need to work that hard. (Hence the headline.)
And that's the thing you can pinch: you don't need perfect copy or killer headlines or the sexiest brand voice if you
really, genuinely get to know your customers.
Yeah, good copy can make an average idea way better. No doubt about that. But it can't do what this campaign does, which is make a customer feel genuinely seen and understood. Like "yeah, this brand gets me".
(Which is why we start every project learning how customers speak and think. Most of the time, they've already written your best copy for you.)