If you do not take into account post-click and post-view conversions, you simply will not be able to correctly assess which channels and how they affect your sales. By lowering target acquisition numbers for display advertising, you can lose users not only in statistics, but also in reality. Either your competitor will influence them with their banners, or they will simply change their minds about buying your product. I remind you that we are talking about 30-70% of your additional conversions.