If you download an Emacs source tarball, it comes with .elc files so you don't need to byte compile anything.
This enables you to compile the remaining (much smaller) C parts quickly: I've seen installs take under a minute!
Related Posts
https://tigerbeetle.com/blog/2025-02-27-why-we-designed-tigerbeetles-docs-from-scratch/ has an interesting distinction between "physical" and "logical" hash of a tarball.
By storing the hash of the decompressed tarball contents (i.e. the logical hash), they can verify the validity of files without needing to keep the tarball around.
One nice feature of cargo that I wasn't previously aware of: you don't need to do anything after updating your Cargo.toml.
In npm, you need to remember to `npm i` after changing package.json. It's not declarative and the state can get out of sync.
I've heard of 'blub languages', where you don't realise that other languages have better abstractions until you've experienced them.
I think the same thing happens with individual features. I've seen several C++ folks miss variadic generics in Rust, but I've not written enough C++ to feel it.