Bitcoin evangelist Jack Dorsey will donate proceeds from his ongoing NFT auction to a charity called GiveDirectly, according to a new tweet.

Last week, the Twitter CEO capitalized on fast-growing NFT hype by tokenizing the first-ever Twitter post (“just setting up my twttr”) through a designated tweet-to-NFT marketplace. At the moment, someone is willing to pay $2.5 million for it.

NFTs are non-fungible tokens—unique digital assets that can take the form of anything on the internet. Everything from visual art to music to journalism has the potential to become an NFT, and individual tokens from brand-name artists like Grimes and 3lau have already sold for hundreds of thousands of dollars.

“But that’s insane!” say the critics. “Why would anyone pay for something you can experience for free online?” 

To that, NFT proponents would probably answer that what you’re really paying for is the idea of ownership—something intangible and knotty, which isn’t necessarily tied to utility. The same concept exists in the traditional art market: it’s why Maurizio Catalan’s banana-taped-to-a-wall piece sold for $120,000. What’s valuable is the piece of paper certifying ownership.

Crypto investors drove up the price for Dorsey’s tweet over the weekend; whatever the final number, Jack has said the proceeds will be converted to Bitcoin and given to GiveDirectly’s Africa Response project, which funnels cash directly to families in Kenya, Rwanda, Liberia, Malawi.

The bidding ends March 21.