Is it a good practice to directly access another system?

There are two ways for systems to communicate (afaik):
1- System that wants to give the command creates an entity with specific component, then the system who wants to receive the command reacts on that component.
2- System that wants give the command gets the other system with "GetOrCreateSystem" method. And calls methods on it directly.

The second way seems a bit off. Since it creates coupling. But I have seen people doing it now and then.
Is it a good practice?

 

Ideally no as it'd be nice to keep systems decoupled and modular and it leads to the question if a system needs to interact with another system should it just not be 1 system?

However in practice sometimes it's just the best way but it does often lead to the mess of having to manually handle dependencies.