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From the article: "it is not about preventing the ink drying on the nib."

Also from the article:

> "In addition to help prevent the pen from leaking, [...]"

So maybe the hole somehow prevents leaks, which would prevent drying in the sense of no more ink :) Maybe it prevents leaks by making the ink at the tip dry out.

The lid prevents leaks by acting as a physical gap between the ball and whatever it would write/leak on :)

Imagine putting a pen, ball down, into a breast pocket with vs without a lid

Not a problem with ballpoints.

Fountain pens are a different matter and many modern pens have perforated caps. The usual fix is a spot of candle wax to seal them up. (The wax can easily be removed with warm water should you feel the need).

A ball point pen dispenses ink by the little ball rotating. So the lid is more to prevent that happening than to stop the residual ink dying.

That said, the only time I've ever had a ball point leak is when the ball is upwards and the ink reservoir opening down, so I would always put the lid on and pop it in the pocket lid down, making a mockery of the clip.