This seems to be yet another variation of the classic, mistaken belief that "your attention is so important that strangers will pay money to send you mail" [0].
It's not a mistaken belief. People have been paying forever for meet and greets, intros, and connections--ultimately it's just an expected value evaluation. There are plenty of celebrities and icons that will make a lot of money off of tools like this. Just look at the success of Cameo. A requirement for such a startup to be successful might be that they require the celebrity to open the email and respond, in order that the customer feels their message has gotten through, but I bet there are celebrities with so much clout that they could probably make money for doing less.
It definitely is a variation of that belief. Could you elaborate on why it is mistaken?
I think:
1. Whether something is valuable can only be discovered if you try to set a price and sell it. Until then, you can not know.
2. LinkedIn has big part of it's business selling 'InMail' at around 2$ per piece. So clearly some people's attention is so important that strangers do pay money to send them mail.