Or I mean, you can just ask if the user is okay with the site running a miner, and if they refuse then don't serve the content. That's what I mean by transparency.
Hardly any website is going to be willing to require non-trivial proof of work before delivering content. It might work for cutting off a streaming video and to a lesser extent as a gate before allowing a large file download, but it's completely implausible for a text-based article. Would-be readers are not that patient.