Advertising on Google or Facebook?
Both platforms can have a great impact on gathering and attracting new customers, but both are very different at their core.
The user that came to your website thanks to Google Ads has searched for a specific service or product at that very moment. As feedback to that query, your website has appeared in the search results, or as a paid advertisement, and in this way you have directly answered this request.
Ads on Facebook and Instagram function differently. You are the one that seeks customers by running campaigns, publishing posts, or by other actions. Those customers might not be looking for what you are offering them, as many people use social media to pass the time and are not in the mood for any offers.
Of course, remarketing can help a lot in this situation, so much so that your ads can appear to someone in a matter of seconds after the person views the product which you or others like you are offering.