I'm sure I would... as a minimum there's password reset emails, payment confirmations & tickets, old friends and colleagues which I'd want to be certain got through to my primary mailbox.... which basically means my primary mailbox is widely publicised information anyway.

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...