Less than a day after publishing the thread, someone did exactly what the researcher described, and was able to cause the bridge to mint and transfer 200 billion BitBTC. BitBTC aims to be valued at 1/1,000,000 of a BTC, meaning the exploiter on paper just landed themselves 200,000 BTC, but this is another case where massive amounts of a token were created and could never be traded for anywhere near their ostensible "value". BitBTC doesn't have publicly available data on the backing of their tokens, but it's certainly nowhere near 200,000 BTC. The project appears to be very new, and was created by a self-described "19 year old Bitcoin believer".
BitBTC has seven days from the time of the hack to fix the issue in their bridge before the transfer is complete and the attacker is awarded the tokens. Meanwhile, the hacker left an Ethereum transaction note to say that "I'm not a hacker, just want to test the exploit with a [proof of concept], won't touch any of the valuable assets."