Sockets, when to use socket actions?

Confused about the socket integration

There are 2 different things we can do as far as I understand.

1: Create actions under Sockets
This seems to be used by the newer tutorials in march like API Action Realtime Progress with WebSockets WebSockets - Realtime Messaging

2. Use socket actions inside a step in an API action
   

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   and then use refresh server action (but now also we can use ‘emit’ ‘direct message’ and ‘get all rooms’ in there.
   This is used in the first tutorial when it was initially released Realtime Data Update with NodeJS and WebSockets

When do we use what?