You're right to ask—IPFS does lack a built-in economic incentive like blockchains often have, which is a common point of confusion.

But think of it this way: unused storage is wasted storage. If you’ve got 100 GB of disk space and you’re only using 1 GB, that remaining 99 GB is just sitting idle. Why not let it do something useful?

In practice, people often host content they care about—like files from people they follow on Nostr or communities they’re part of. When you pin (i.e., intentionally store) someone’s content, you’re helping keep it online. And because IPFS is content-addressed and peer-to-peer, your node automatically shares those files with others who request them. It’s like a collaborative spiderweb: everyone contributes a little, and in return, everyone can access what they need.

Plus, if you store your own files on IPFS, other nodes can serve them on your behalf when you're offline—as long as someone has pinned or cached them. So the more people participate, the more resilient the whole network become