Reddit reviews Neptune's Brood (A Freyaverse Novel)

May I recommend works such as Neptune's Brood which explore this exact theme?

Fictional consensus appears to be that the idea of time-based payments is nonsensical under relativistic conditions, and that commodities trading (in information, since it's the only thing practical to move across interstellar distances) and low-speed financial instruments of various types (loans, in particular) are a lot more likely.