What are the limitations? For example: if I have a Python script that makes some HTTPS requests, will this runtime provide to my compiled binary everything it needs to perform this task?
The idea behind the project is to run WebAssembly modules in Kubernetes. You would have to compile your Python script to WebAssembly before it could be executed.
If your WebAssembly module complies with the WebAssembly System Interface, Krustlet can run it.
It's important to note that the WASI standard and wasmtime are still under heavy development. There are some key features (like networking) that are currently missing, but will be made available in future updates.
It sounds far-fetched, but I think it may eventually become practical with WASM and WebRTC, to use peer-to-peer networking for distributed computing.
Closest example in that direction, I've heard of malicious WASM payloads that mine cryptocurrencies:
Persistent drive-by cryptomining coming to a browser near you (2017)
https://blog.malwarebytes.com/cybercrime/2017/11/persistent-...
I'm optimistic that people will find socially beneficial application of this idea.
I can't answer your question exactly, but I assume that it can run any compiled binary.