MS also have their own take on WebAssembly
This software (Wasmtime) allows you to run webassembly code from within .net.
Though I agree it could be a nice way to make software avaiable on all platforms.
Kind of like using Google translate to go from English -> Something -> English. In theory a perfect translation would give you back your original input exactly.
Of course this should be more feasible with programming languages than with human languages.
Last time I looked, blazor compiles c# to MSIL just like normal, but also provides a wasm runtime for MSIL.
At least that is part of what was communicated so far.