There are drama seekers and there are drama creators. Some people live their whole lives in those camps because it's "exciting". Many of us prefer "boring" for its stability. We value peace and predictability and want that for a platform from which to spring exciting things...
On her own, KA had at least one maxed credit card, no livable residence (outside of the home of her intertia-driven [see what I did there?] bf), apparently no access to a cashpile (didn't settle her Botox walk-off) and had to sell her vehicle to get some money fast.
I think we're starting to see her for what she's always been. A salesperson, and not the good kind. A poser.
She is attractive and probably talks a convincing game. As a real estate agent, she may have wooed CS into forking over some capital to invest in real estate, as rentals or flips or long-term holdings. Someone upthread pointed out that CS's $450,000 isn't likely cash but value in properties he feels he fronted.
That tattoo parlor where she met her dinner and weed buddy, where she was waiting on friends? Really? She suddenly had some after being described as mostly a loner? Did they ever emerge? Or did "Ari" say she'd just text them (ahem) to carry on without her, her biffs (best imaginary friends forever), launching into her next metamorphosis? Bet she's done a lot of shape shifting over her lifetime.
You know what's most threatening to someone like that? The real deal.
So she gunned her down.
JMO