A newsletter sign up keeps the person engaged and potentially coming back over the months and years that they get those LeoFinance Newsletters in their inbox. Every week they'll continue to get that newsletter and I suspect that the brand recognition that brings over time will eventually lead them to "hey what's this LeoFinance thing and how can I start earning?"
This sounds really dope and could bring in some big investors and hardcore users. Besides keeping people engaged to the Leofinance's updates, the newsletter would be a key reminder and would ensure people have their leofinance always on their mind.