From Coinhive's front page:
Will This Work On My Site?
Technically yes, economically probably not. If you run a blog that gets 10 visits/day, the payout will be miniscule. For the captcha and shortlinks with a sensible hash goal (1024–16384) you'll need to have a whole lot of users to make this worthwhile.
Implementing a reward system for your site or game where users have to keep mining for longer durations is far more feasible. With just 10–20 active miners on your site, you can expect a monthly revenue of about 0.3 XMR (~$95).
If you run a streaming video site, a community site, an online game or anything else where you can give your users an incentive to run the miner for longer durations, then by all means: try it.
For the miner to generate a lot of revenue, you either need a lot of traffic (in which case, it might be more efficient to just use traditional ads anyway) or need to keep the user engaged with your application (so that you can keep using their CPU). 2 minutes doesn't look like sufficient engagement to me.
By the way, since the application want to keep you glued to the computer screen so you're willing to let the application sap your spare CPU, your attention is being sold (though your private data probably isn't).
