It is actually the opposite. I want to know why people don’t feel comfortable charging to contact them via email.
I think that goes for most people.
It makes a little more sense to charge for a guaranteed response as LinkedIn does indirectly...
And most people have potential clients, casual acquaintances etc that would enrich their life by contacting them, but certainly wouldn't pay 0.1 BTC to do so, so I'm not sure I'd ever stick pay-to-email as a contact on a business card or website. Those people whose email addresses people would happily pay for tend to be able to pay for assistants to screen their primary contact email anyway...