What part of the delegate gets passed back?The return type?

I'm a little bit confused about this. Here's the example by a user called LightStriker that made it click for me, but there's one thing I don't get.

 public class One
     {
         public delegate void Enter (int x);
  
         // Static is only needed if you want it to be static. It's like a variable.
         // If the event is related to an instance, it should not be static.
         public event Enter OnEntered;
  
         public void Enter()
         {
             int myInt = 0;
             if (DateTime.Now.IsDaylightSavingTime())
                 myInt = 1;
  
             // It is up to you to fire an event.
             if (OnEntered != null)
                 OnEntered(myInt)
         };
     }
  
     public class Two
     {
         private One one;
  
         public Two()
         {
             one = new One();
             one.OnEntered += Method;
         }
  
         private void Method (int y)
         {
             if (y == 1)
                 Debug.Log("Day Time Saving!");
             else
                 Debug.Log("No saving.");
         }
     }

My current understanding is that Enter (int x) sends the parameter to the subscribing method in another class. Just like in the example and int Enter is set to either 0 or 1 and then when the event is fired, that int is passed in as a parameter and is read by the subscribed class.

Now what if I had a return type other than void?

If I had a

     public delegate float Number (int x);
     public event Number OnNum;

then would that mean that the subscribing method in another class will get the int from here, but return a float to the delegate? I've read that it isn't a good idea to have an event with a return type, but I never quite gathered as to why was that so bad. At any rate I'd appreciate some clarification on the matter.