Starting from the 1st of April 2021, Google will remove the Showcase Shopping ad group ads. No need to worry. Google Shopping Showcase Ads will be part of the regular shopping campaign.
Showcase Shopping ads are carousel ads that allow you to show a range of products instead of a single product listing. This is an excellent adverting option to create brand awareness and offering your catalog.
Showcase shopping ads were purely designed for generic search terms. IE users who are in the research phase of the buying intent.
With the old showcase shopping ad groups, you could not assign any automated bidding, such as ROAS. Instead, you are required to use manual bids. While you could technically select ROAS, the campaigns would simply not run.
With the new setup, that means all automated bidding settings are available.
Showcase ads are only intended for generic search terms. With the previous campaign setup, you could target only showcase ads and build up your negative keyword list to only show for search terms you want. And not have this affect your normal product shopping ads.
If you exclude a search term with the new merged ad group types (showcase ads + product shopping ads), you exclude both kinds of ads. This severely limits your business objectives, further limiting control.
As we all know, Google is heading towards full automation, the decision to merge shopping ad formats is expected.