An interpreter is significantly easier to sandbox than native execution, and it means they can make guarantees the host system won't crash no matter what the program running is.

I could see it being useful for allowing third parties to run experiments on their hardware in space without having to manually verify the code safety.

I can think of a few potential advantages:

1. Portability: It means you can change your hardware target and you only have to worry about re-certifying this, instead of an entire compiler.

2. Testing: You can probably run your WASM code fully deterministically in a deterministic simulation much easier than native code. Also when developing you don't need the actual hardware.

3. Isolation / compartmentalisation. If I were them I would be strongly considering using the WASM component model (in future).

It would be good if they put their actual motivation in the readme though.