I could see an argument where Rust is performant and low level enough that you can use it at the bottom of the stack, and has good enough abstractions that it's productive to use higher in the stack. There are certainly benefits to using one language for everything, but this logic reasoning relies on you having a team that is very familiar with it, and having your bits of tooling and libraries worked out for your setup.
Yep, exactly. Lower-level languages however also give you much more foot-guns.
These days my ideal app is written in Elixir for almost everything due to the insane parallelisation and fault-tolerance that it offers (and the copy semantics that make shared memory bugs impossible) with Rust sprinkled at the critically important-to-be-fast places -- like working with sqlite3 for example.
All of that could be achieved with Rust or any other language really. But it requires tons of tooling, CI/CD jobs, Git hooks, static analyzers, linters, formatters etc. And a good chunk of all that doesn't even exist for many languages.
So I prefer to make my own blend that has the important advantages at the right places.
