Yield complete block in ember

I wondered how I can yield the complete block wich I pass to my component. I already found this http://ift.tt/2e0ynFn but I dont understand why there is

//my-component.hbs

  
  
   ...

Why I have to name what I want to yield? That makes no sense because I want to yield (display) the whole block wich I pass to the component, regardless what I do there.

So I tried just to use yield only:

//my-component.hbs

   ...

and use the component this way:

//myroute.hbs

   - 

This dont work, but I expected that 'car.name - car.color' will be rendered in the of the component...

Can someone explain me this, pleasse?