WooCommerce reports products one at a time. What sold, how many, at what value. What it doesn’t say is which ones travel together.
Squizzie counts that from your order items. A pair has to appear in the same basket more than once in the period before it shows at all, so every row is a repeat rather than two things that happened to collide one Tuesday.
What it isn’t
It isn’t a recommendation engine. It doesn’t rank, it doesn’t score, and it won’t put a "customers also bought" strip on your product page.
It counts what actually happened. What you do with that, whether a bundle, a shelf position, a cross-sell, or just knowing, is yours.
Why the distinction matters
A recommendation engine guesses at what someone might want. This tells you what people already did, which is a smaller claim and a more reliable one.