Although it would be a complete waste of time and focus trying to build your campaigns by using Vanity Metrics as a base, you might want to consider if your target audience is consumers.
Although business owners understand vanity metrics and it might work against you by making you look desperate for attention, when you are selling products or services to a consumer market, you often need to remember that a lot of the market still favors heavily watched and shared content. This means that you can leverage the low cost of promoting your image, video or text content to pump up the statistics and then use the staged content inside of your advertising campaign.
Social proof, data collection and retargeting is the where you need to focus.
The value you gain from engagement is derived from the data you collect and the social proof provided on your ads. Use an engagement campaign to collect the proof, then use the post id to bring that social proof with you to your ad campaign.
Use video’s to capture attention then use retargeting to get in front of a warmer audience. If your not planning these campaigns out properly, your doing it wrong.
Value will always win the race, do not take this as a replacement to producing high quality content that is not saturated by the majority of advertisers. Although this may give you a better ROI by increasing organic engagement and capturing the audience that cares about the metrics, 100% increase in ROI from 0 is still 0.