Application plugins could also be wasm. That lets plugin authors write in any language they want and have their plugin work.

That's the idea behind the Extism framework:

https://extism.org/

uBlock Origin uses WebAssembly in Firefox for better performance:

https://github.com/gorhill/uBlock/wiki/uBlock-Origin-works-b...

The closest way to visualize it is probably how cloudflare offers something kind of like a container (if you squint) via it's workers product.

https://blog.cloudflare.com/announcing-wasi-on-workers/

I assume the merit for cloudflare is lower overhead cost per worker than if they had done something more like AWS lambda. Explained better than I can, here: https://developers.cloudflare.com/workers/reference/how-work...

It does currently present a lot of restrictions as compared to what you could do in a container. But it's good enough to run lots of real world stuff today.

> I don't understand WASM, but I read that a big draw of WASM is it's ability to provide portability to any language. This would mean Python libraries that depend on an unpopular C library (which could be lost to time) could instead be a single WASM blob.

Yes, this is a key value of WebAssembly compared to other approaches, it is a relatively (compared to a container or a full blown VM) lightweight way to package and distribute functionality from other languages, with high performance and fast startup. The artifact is minimal (like a static/dynamic library, depending on how much you've included), and if your language has a way to run WASM, you have a way to tap into that specialized computation.

I think that looking at it in terms of Embeddability is more useful compared to portability.

In the sense that compiling C to any language is easily done without too many problems, what wasm allow is to have a secure and performant interface with that language.

For example IIRC one of the first inclusions of wasm was to sandbox many of the various codecs that had regular security vulnerabilities, in this Wasm is neither the first nor the only approach, but with a combination of hype and simplicity it is having good success.

as in https://arxiv.org/abs/1912.02285

Basically yet another bytecode based runtime, but being sold as if it is the very first of its kind, despite prior history.