Nobody suggested using untested code, parent said they’d trade a small amount of perf for more security. I do think a lot of people would make that trade, all else being equal, once a viable tested replacement actually exists. HLLs exist in the first place because a lot of people are willing to trade a little perf for more security, faster development, and lower costs.

That said, nobody’s disputing that a “lot” of people care about performance. It’s worth taking a look at the last slide of the presentation, which states clearly that if you care about performance, you should use C:

    Performance is paramount ⇒ use C (up to 15%)
    Minimize memory use ⇒ use C (↓ mem. budget, ↑ GC cost)
    Safety is paramount ⇒ use HLL (40 CVEs stopped)
    Performance merely important ⇒ use HLL (pay 15%, memory)