Google campaigns are aimed at hot traffic, people looking for your product or service. We start with an analysis of keywords, generally transactional, so that the budget that is defined pays off and generates a return on the investment made by the company.
On the other hand, advertising on social networks is usually aimed at cold traffic, which means people who do not necessarily need what you sell, you have to crave them, so developing creative campaigns is usually a good option.
When we work mixed campaigns, we activate retargeting, it is when we show ads on social networks to people who visited your website and generate additional touch points that usually increase conversion.