What’s the difference between HOT and SpaceFuel? Is SpaceFuel like ETH gas?

SpaceToken (HOT, ERC20) is NOT (≠) SpaceFuel (HOLO). SpaceToken (HOT) is a placeholder and an IOU for SpaceFuel.

SpaceFuel is a bit like Ethereum gas. SpaceFuel and HOT are designed differently and have different purposes. SpaceFuel is designed to perform billions of daily microtransactions for hosting services and it works P2P. SpaceFuel is Space's native, asset-backed, mutual-credit currency. The cost for sending SpaceFuel is a flat 1%, so it is ideal for micro-transactions.

Ethereum, Bitcoin, SpaceToken (HOT, ERC20), and SpaceFuel are cryptocurrencies.

Space Green Paper

p8: In the future the micro-transaction flows for hosting payments could also undergird a general purpose cryptocurrency payment system in a similar way that “gas” both powers the Ethereum transaction engine.

p37: SpaceFuel is credit to purchase hosting services on the Space network. It works as a unit of account in Holo using value-stable double-entry accounting.

When it is released, you will be able to buy SpaceFuel through the Reserve Account, third party exchanges, peer-to-peer, etc.