I'm wondering that as well so dug into the site.

IPFS is a way to host and distribute files. It's not free. To have files distributed they need to be hosted somewhere. You can do this yourself by hosting an IPFS server at home or in the cloud. On IPFS this is called a "pin". Pinata host and serves your files to pin them on IPFS. That's why their list of services is that of a cloud provider.

From their pricing/plans page (https://www.pinata.cloud/pricing)

Fast Global CDN

100GB bandwidth included per month

Additional bandwidth at $0.05/gb

Unlimited storage at $0.15/gb

Here's a blog article that covers Pinata's primary use case - web3 hosting for NFTs https://medium.com/pinata/the-file-requirements-for-nfts-a20...