Even if you don’t profit but place what looks like smart bets

A casino or bookmaker doesn't need to heuristically identify betting behaviour that's 'smart'. They don't need to spot evidence that could be hidden by good opsec. No need to find micro-expressions or hidden cheating gadgets. Nor to do background checks to know you've got a buddy with insider knowledge.

All they need to do is check if you're cashing out more chips than you came in with.

It's not trivial for the casino to track this against a determined adversary. If you're already thinking about "good opsec", you can get someone else to help cash out your winnings.

A buddy from out of town, or a losing regular, or a poker player who the casino doesn't care if they win. In Vegas some casinos' chips are negotiable, officially or unofficially, in other casinos.

Exactly - they don’t need to catch you cheating, they just need to decide you’re bad for business

You can just jump bookies.

Except in the state of MA.

They rightfully passed legislation banning such practices. The idea is that if casinos and bookies refuse to cap your downside, they have zero right to cap your upside.

Not everywhere. Circa wants winners.