[matkoniecz]

"This primitive alone allows for much higher velocities of money since value can be moved and repayed in a single block (on the order of 10 seconds)."

what can be usefully arbitraged in that time in way that guarantees no loss?

[exo762]

It's actually way funnier than GOP presets to be. Flashloan must be paid back in the same transaction. Since whole thing happens in the same tx, it's atomic. So you can use smart-contract logic to determine if you are actually making a profit, and if you are not - revert!

[wmf]

Exploiting contract bugs.