Hello Rivas, thank you for your great question in the FeedArmy AMA Event.
So with my clients depending on what they sell I use one or the other. However even after maybe several months I might change.
One test I do is if the ROAS is too low using PMax with assets, I change it to PMax without assets to see if the ROAS increases. Usually, it does. In this case, I will then set up separate text ads in combination.
The feed-only setup does indeed lower the sales volume, however, profits are higher.
I use automation if the account is too big. For example, if a client has 25k products, this is hard to manage, so I setup most based on automation. Then set up manual campaigns for specific goals and tests.
Increasing conversions is difficult, especially when merchants/business owners are still thinking about the sales growth during COVID-19. So on one side, we have to be realistic that growth will no longer be 50%+ but a more realistic 15% to 20%.
So if your sales growth is stagnant, improving the data feed quality, website landing page, and then the campaign setups are key to getting that sales volume up.