It matters to whoever is paying for compute. If you get some other benefit, it may be a worthwhile tradeoff, but it always matters.
This kind of attitude is how we get bloated Electron apps that HN (including me) loves to complain about. Speed should be a first class consideration, not something to throw away for later.
> No one is gonna be able to tell Rust vs Go in a web API
Debatable, Discord moved from Go to Rust [0] because they were getting latency and CPU spikes from Go's GC, and I'd assume that's the same with any GC language because, well, the GC has to run sometime. Now you might say that we're not all Discord scale, to which I'd say, like above, there are benefits to Rust that are more than just speed. Cargo alone is nigh unbeatable compared to some other languages. I was trying to get Python to work the other day and was pulling my hair out over venv, virtualenv, pip, conda etc.
And the discord instance was because it was systems/performance critical software they rewrote. They didn’t rewrite there web APIs. Discord mentioned the rewrite is now rust with C++ glueing it together. No way you are using C++ unless you have to.
I’ll agree with you on python venv/pip. Ugh what a mess. I like cargo, but honestly I think you could argue cargo also is an issue. When you bring in 100 crates, you just gotta hope all the unsafe code in them are safe.
A static analyzer found 200 memory unsafety issues in rust crates: https://www.infoq.com/news/2021/11/rudra-rust-safety/
Memory safe GC languages you don’t have to worry about that, and you can get a package manager.
Speed equals money. The same app running at twice the speed uses half the compute resources. You may also gain a lot of simplicity if you don't need to distribute your architecture so early on.
Speed is the only one you may possibly not, but I think speed is an non-issue. Speed in programming never matters except in the systems space. No one is gonna be able to tell Rust vs Go in a web API and depending on how you do the benchmark, I think many GC languages can probably tie Rust.