Hope, Zeal, and Augur all share a common mechanic where you can discard them to test at a base of 5, and the test is automatically successful. This means that the test difficulty is 0, and no chaos token is drawn, but you still get to commit cards to the test. In other words, you get a guaranteed success by (at least) 5, and you can make use of this to assuredly trigger not just cards that have if successful effects, but those with succeed by X effects. Cards with automatic successes aren't terribly common, and the cats provide a reliable, repeatable way of getting them.
Since you have to trigger a Fight / Investigate / Evade action on the cat itself, this is limited to skill cards and reaction abilities on assets. Most of the succeed by X cards are in the faction, making a / pairing an ideal investigator choice. skill cards include Quick Thinking, "Watch this!", and Nimble at 0xp, and Momentum and All In with XP. For assets, there is Gregory Gry, Pickpocketing and the Lucky Cigarette Case.
Succeeding by 5 maxes out every single one of these cards so far (except upgraded Lucky Cigarette Case), so you get the full benefit. The downside is that you forego the benefit the skill icons would have provided. This isn't such a big deal for Vicious Blow or Deduction, but something to consider for Overpower, Manual Dexterity and the like.
In the faction, you have Drawing Thin, a repeatable, stacking source of income with absolutely zero downside to using, that completely breaks the game.
Moving on.
Preston Fairmont and Wendy Adams have the best access to these cards, with Preston benefiting particularly well from the regular use of the cats' elevated stats. Preston is also the only investigator so far to be able to take Miss Doyle and All In + the upgraded Lucky Cigarette Case, guaranteeing a 5 card weakness-free draw, or a 1 in 5+ filtered draw that is (hopefully) also weakness free. (Actually, Lola Hayes can use the LCC too but this is a terrible idea, putting the cats at risk on one turn and the LCC on the other). Wendy, with her 4 and investigator ability, is a lot less impressed by these shenanigans.
In multiplayer of course, one investigator doesn't have to do everything. A player can trigger an automatic success with a cat, and the rest of the team can pile on skills. The skills above, as well as skills that are valued more for their effects than icons (Resourceful, Inspiring Presence, Eureka!, Enraptured etc) are all great candidates. Someone with Crystal Pendulum can also get a free card draw out of it just by being at the same location and predicting which way the fur flies.
As you can see, the cats are very multiplayer friendly and a great combo initiator. They are a very interesting deck choice for Preston as well, giving him a path to oversuccess other than stockpiling money. He still needs to find Miss Doyle first though, so don't neglect card draw.
P.S. There is one event that modifies an existing skill test, as opposed to initiating a new one. Sadly, tossing Zeal isn't considered a projectile attack, so Marksmanship does not work. Maybe one day we'll get a Cat-apult card?
Edit: Added Drawing Thin..