If you want it to be “free to most users”, the cost of data storage and IO will completely dominate over the cost of CPU.

There are plenty of good arguments to prefer Rust over python for a distributed application, but “language efficiency” is not one of them.

Anyway, if you are biased in favor of Rust and want a decent argument to justify it, I will let you use ‘It’s easier to compile Rust to WASM and have the application run on the browser, while compiling python in a cross-platform way is a nightmare’, free of charge.