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 OP_CAT has been live on Bitcoin Cash (and Liquid IIRC) for years.

Please demonstrate how dangerous it is by exploiting the weakness you claim those networks have adopted. 
 Hmmm, not sure if you realize that bcash is already horribly centralized. This is what we’re trying to avoid with bitcoin. 

Also, there is no risk to OP_CAT on Liquid because it doesn’t have mining like bitcoin. 

The problem with enabling OP_CAT on the bitcoin timechain is that it can create arbitrage opportunities which can encourage miner centralization. 

Here’s how:

CAT can enable on chain atomic swaps. 

https://bitcoin-takeover.com/andrew-poelstra-bitcoin-covenants-op_cat-vs-op_ctv/

On chain atomic swaps can be used to create securities marketplaces (eg Uniswap on Ethereum)

https://www.gemini.com/cryptopedia/what-is-an-atomic-swap-token-swap

Unswap-like exchanges create the potential for centralizing MEV by allowing speculators to bribe miners to reorder transactions so the speculators can jump the queue. 

https://medium.com/flashbots/frontrunning-the-mev-crisis-40629a613752

Smart contracts, arbitrary code execution, etc are fine if they’re off-chain. But if when they are used on-chain, then the they can harm bitcoin’s decentralization. 

Devs who want to use OP_CAT should just use it on Liquid. No need to take unnecessary risks with bitcoin. 
 Definitely agree with the conclusion. Not able to argue any of the argumentation though. 😵‍💫 Thanks for sharing 🙏 
 The world's best attackers are not motivated to crack those shitcoins. if I was a cracker who found a vulnerability in OP_CAT, i would push to get it added to Bitcoin so i could actually benefit from my work. 
 And it keeps looking like they’re trying. Udi from Taproot Wizards seems to be a big proponent of OP_CAT. I assume he wants to make bitcoin a shitcoin (“innovation”) paradise. 

https://www.coindesk.com/tech/2024/04/24/op-cat-proposal-to-bring-smart-contracts-to-bitcoin-finally-gets-a-bip-number/