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.
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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.