I think the main difference there (apart from the feature being deprecated over a decade ago) is that Coverflow stored a single thumbnail, from which you couldn

I think the main difference there (apart from the feature being deprecated over a decade ago) is that Coverflow stored a single thumbnail, from which you couldn't derive much information - it's metadata alongside your browsing history, but not much more than that. Meanwhile Recall takes a stream of high-quality images, from which a full reconstruction of your entire computer-use activity over the last 90 days can be reconstructed in high fidelity and searched through. From a security point of view, the threat models are a world apart.