I think the site is right about the "coins" method. If I had an automatic subscription of $10/month to refill my news wallet, and I could pay $0.05 out of it to read an article, I'd do it, especially if it was a use-it-or-lose it system.
In fact, if they charged $0.20 per story if you pay directly, or $0.05 per story if you pay out of your auto-reload wallet, I think that could incentivize users to subscribe.
Of course, it would have to be shared across every newspaper, and publishers hate that. Apple News is the closest it's gotten - the app sucks, but you can share articles into it to remove the paywall and that works great.