Sending a message, handing off a file, publishing software, and retaining information over time are four different problems that need four different systems in a decentralized app.
On
@Polkadot, they are all part of a unified, automated system.
Celerity moves small messages quickly. Levity handles asynchronous handoff of larger data. Bulletin publishes app bundles and shared content. Capacity creates a longer-term storage market.
One generic storage layer cannot do all of this well. The Product SDK means developers do not have to wire it together manually.