WASM + Zig (even compiling C code) will make some really tiny WASM files with no dependencies. The problem is that you don't have a standard library, then your code gets really big as you add more of that in there.
Exactly right. 2.7KB works because it's pure computation — slot counting, no allocator, no stdlib, no WASI. The moment you need I/O it balloons. This use case fits a glove