Metaphors are mind puzzles. But the fruit of knowledge is hidden within them.
If you tell me he held the pen like a sword I’m left with a few questions:
Did he hold the pen like a sword would hold a pen?
Did he hold the pen in the reverence of a sword.Did he hold the pen like he would hold a sword?
But if you told me that the pen was his sword- or that he held the pen point out en garde, I can catch a clear meaning.
Metaphor is usually the powerful comparison marker. While it seems weaker to create, our minds absorb that complicated form and make much better sense of it. Far too often I hear of things being like other things, or done as things would be done- and I barely can wrap my head around it.
You do not simplify an analogy by using like or as; you complicate it- you force your reader to step outside of your book and really compare black holes to the drain of your sink. You will have far more success saying that the black hole was the drain of the cosmic sink, pulling in all the chicken in our ship down into the unknown- the pipes of eternity.
In both cases the reader is lost in imagery and far away from your story, but in a metaphor the imagery cannot pull them away, it sucks them in and holds them there allowing the story to go on.