The very tail end of this product concept for "smart landline", two decades later, was the Amstrad Emailer, which had all sorts of features to maximise its use of premium rate billing. It was universally regarded as terrible.
A premium for checking email is an interesting concept, I could see people wanting to sign up for this now as a way to reduce the compulsive need to check for new emails
Aren't there extensions to control compulsive checking of websites?
Yes but I'm thinking of the type of scheme people use to lose weight. "If I dont lose 3 pounds this month I'll owe you $10" but for email or media usage