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You can only exchange cards you have at least three copies of, so there's no chance of accidentally getting rid of cards you need
They are often light on interaction and easily fold to whatever combo your list has
On the topic of outside cards, I also feel Gizmek Naganaki, the Sunrise Signaler is almost a requirement, being able to turn itself into your level one playstarter, or filter either big machine (In Turbulence or Fire Engine) into other tools
Some argue that these consistently powerful strategies involving combo elements arent always fun to play against and may not be in the spirit of Commander, but I think setting clear expectations with your playgroup will help curb frustrations