Yes, and we recommend it. In the US, advertisers running free listings and ads together on the Shopping tab have seen an average increase of over 50% in clicks and over 100% in impressions, with small- to-medium sized businesses seeing the largest share of increases.*
Your store is automatically opted into free listings, and can you choose to run a paid Smart Shopping campaign.
* Source: Google Internal Data, July 2020, based on an A/B test comparing performance for users seeing the updated layout on the Shopping property vs a control group not seeing the new experience.