One With Nothing actually works with a few decks (especially black) where you operate through your graveyard. A couple of lich decks, certain mill stratgies work off of discard mechanics etc. It also works especially well if you have the ability to case a card from your graveyard for free (like say psychic spiral) or if you have creatures on the field that get bonuses from things being in your graveyard. The fact that you do not see potential decks past a very very limited scope makes me question your creativity in deck building.

Second card is meant for human token spam decks. Since you can use 3 of your tokens to remove a creature rather than say 6 or 7 (if it is a green creature) then you gain immediate advantage, and since it is a repeatable removal spell, it shows that there is benefit, albeit the downside is they get a 1/1 flying creature but that means they would still have to swing like 20 times in modern (40 in EDH) to kill you with the spirit or they will have to block one of your human tokens, cause remember, its about spamming tokens.

Repeating barrage costs a lot and the only time I would use it is in one deck for infinite combo games (where everyone has decks built for infinite) and even then, it isn't the best but because it is repeatable so easily, it works.

I would prefer to draw, and play with, a simic sky swallower over a lot of the janky shit they create now. Sure its a filler rare but if you are going for a win then free casting this thing is a good way to do it.