based on that website, it sounds like this whole thing is a marketing campaign for that mailscarp service. They don't actually want you to read their newsletter, they want you to go investigate and then sign up for their 'block spam' service.
Not only are they a terrible service that lies about their data scraping, their service also doesn't even work. I entered one of my random email addresses that can definitely receive email into their tryout screen and it got almost every detail wrong except for the "format" fields.
If they are particularly unscrupulous, there is an unsubscribe link: they capture use of this link to validate emails, then aggregate and sell that information onto other spammers.
WAG: I think in general people think building any kind of email distribution list can be monetized, even if it's not being done immediately. Either sold off wholesale or directly monetized through adverts / affiliate links.
