Why does "Use Device Timestamp" make my Game Audio go out of sync?

[PrinceVinc]

Yesterday, when I streamed with PS1 Emulator Duckstation, my Audio wen't out of sync, disabling "Use Device Timestamp" fixed the issue after a brief Google Search.
Why does that happen? And why is "use device timestamp" enabled by default when it can make Audio go out of sync?
Should it not do the opposite and keep it in sync?

 

[PrinceVinc]

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