Because they're claiming that only 6% of shoppers are successful with searching for products on e-commerce sites. They imply Google can help prevent the 94% who "abandon their session" because of inadequate site search. It's a garbage claim even when accounting for poor quality or broken site search.

> e-commerce search absolutely sucks

Any examples? To qualify as an example, the site search would need to fail to return a product for a given phrase that Google search otherwise finds.