That's not a fair reading. I don't see anywhere that the article makes a any suggestion about when to optimize, it only suggests techniques that you could presumably use when you actually need to. Just as it's silly to prematurely optimize, it's silly to toss these suggestions out the window. If you hit a point where you need to optimize, these suggestions can be very useful.

> You're also fighting JIT assumptions, since all VM devs will attempt to optimize against common patterns

Optimization nearly always means that you're optimizing against a particular implementation, which may not be the same in the future. But your app lives today, in today's world. If you actually do hit a bottleneck, should you throw up your hands and say, "Don't worry, I'm sure it won't matter in a few years?" Of course not. Just as you shouldn't prematurely optimize, you should be willing to do it when necessary. Having some knowledge about what might work is definitely helpful.