Why make certain cards larger? Are they more relevant to the user? Are they based on the user’s previous interactions?

If they’re just random, then it’s distracting. Why does the user want to see some random junk. It feels like an advertisement.

Most importantly, this breaks the entire visual flow. As an e-commerce store shopper, as a website visitor, as an app user, I am there to find information. I’m not there to look at your pretty design. I want to scan the page quickly, and click on whatever I want more info about.

The user will have an easier time browsing the products if they’re all the same size. Less distracting, more cohesive. Less frustrating.

A more pleasant experience makes the user much more likely to come back next time they’re looking for something.