throttle(() => interval(500)) vs throttle(() => timer(500))

[freiondrej]

Hello,
if I understand the behavior correctly, throttle(() => interval(500)) behaves the same way as throttle(() => timer(500)). Is there any difference in using interval() instead of timer() for throttle()?
Or in the use case with throttle(() => interval(500)), which waits for completion of the provided observable, throttle() will never emit because interval() never completes?
Thank you!