As you can read in the whitepaper, Engagement Token wants to create a decentralized efficient marketplace for advetisers and publishers. Users rewarded with Engagement Tokens will be able to sell the tokens back for example to advertisers, who can then use them again to buy ads.
Directly quoted from the whitepaper:
''On the Engagement Platform, publishers sell their inventory directly to advertisers with no middle man enforcing an auction that mostly benefits the aggregator. Advertisers set the price for specific articles based on the objective value of engagement, creating transparency and trust in the marketplace.''
''DECENTRALIZED ADVERTISING. Blockchain technology has proven the tremendous power of decentralized systems to create efficient marketplaces.''
''Engagement Tokens are used by publishers to reward their engaged audience and allow ad buyers to acquire advertising space on a dynamic marketplace uninhibited by legacy ad serving and banking technologies.''
So, once more information is available on how exactly this will be possible we will notify you!