I just feel like i'm missing something
In the games that you can catch them in, if you catch all the kinds of unknown, a special event will happen, like a door opens, or a character in the area will say something new and give you something. Other than that, they only have one move, so they are usless in battle, but they give good experience points to low level pokemon.
Depends.....it could be used as death blocker where it stands in to faint so another pokemon can live. Thats the only use i ever got out of mine.
You can make use of an Unown holding choice specs/scarf with the modest nature and in my opinion is dragon the best hp type for Unown because it is only not very effective against steel.