You supposed to have only a single event loop per thread, the standard event loop policy ensures that the value is thread local (you can change that by modifying the policy), unless you're doing something unusual with multiple loops in the same thread you will never need to pass the value.

Also if you are passing the loop and are doing multi threading, you need to be careful, because if you pass it to another thread you might see weird issues.

I initially also started explicitly pass loop around but once decided to combine asyncio with threads I realized that it is better to trust get_event_loop() to do the job correctly. The only exception is when I need to schedule coroutine in one thread for another thread. In that case I need loop from a different thread so I can invoke call_soon_threadsafe().