I am still unsure about that. Their JIT is fully written by AI, which makes me very nervous to ship it. In a web browser,
around 50% of all vulnerabilities are caused by the JavaScript JIT. Shipping a JIT that has not been fully audited by humans is a poor idea in my opinion. Additionally, AI cannot fundamentally write a well-designed JIT, as JIT requires very low-level programming involving a near-complete knowledge of the CPU architecture that only highly experienced individuals such as Cameron Kaiser have been able to pull off. In short, AI is unable to write such highly specific and optimized code.
In my opinion, adapting the TenFourFox JIT is still a much better idea, and I would rather ship JIT-less builds until a human port (or at least a port that is fully audited by humans) can be done.