I do understand that only a pencil allows you to make notes in the margin of a page without defacing it forever, but then I've never been keen on physically altering books. Their magic really does take me over with reverence for the object, no matter how pompous that may sound. In other words, this potential benefit of a pencil over a pen doesn't do it for me.
However, the key benefit for me of a pen is that the destruction of a draft is far more difficult than via the delete key or a rubber. In a moment of frustration or rage, a keyboard or a pencil would enable me to get rid of text forever far too easily, thus cutting me off from a way back. Without the evidence that's left behind by the ink of a pen, how could I retrace my steps through the creation of a poem and salvage a turn of phrase or realise where I'd taken a wrong turn? I often even return to drafts of a second or third attempt while tussling with the sixth or seventh version of a poem.
However, the key benefit for me of a pen is that the destruction of a draft is far more difficult than via the delete key or a rubber. In a moment of frustration or rage, a keyboard or a pencil would enable me to get rid of text forever far too easily, thus cutting me off from a way back. Without the evidence that's left behind by the ink of a pen, how could I retrace my steps through the creation of a poem and salvage a turn of phrase or realise where I'd taken a wrong turn? I often even return to drafts of a second or third attempt while tussling with the sixth or seventh version of a poem.
In summary, a pen always wins out over a pencil when I'm writing poetry. A keyboard, meanwhile, comes a very distant third. What about you?