What makes me uncomfortable is the ruggedness of a peanut lighter depends entirely on the seal at the O-ring. If the O-ring breaks or if the lighter otherwise fails to have the seal, then you have a lighter that is suddenly on the delicate side. Without the seal, the lighter will have basically zero water resistance. I would expect a peanut lighter to be entirely inoperable for the remainder of a trip if the mechanics are exposed to heavy water. Also, the lighter fuel will leak relatively quickly on a peanut lighter without an O-ring seal.

In contrast, a mini Bic just needs to air out for awhile if it gets wet. Also, the mini Bic doesn't have a gas leak issue (at least not for me).

Here's an invention idea: a lighter with a head unit as rugged as a mini Bic lighter, but with a covering like the peanut lighter, and less than $10. My temporary homemade solution would be to put a mini Bic inside a larger capsule that's waterproof. I would bring this setup if I'm venturing into extreme conditions somewhere, along with other other fire starters of course.