Using WASM to make cross-platform code run in browsers isn't any more weird/esoteric than targeting Android via the Android NDK. The least painful way is to do some things in the 'native' platform language (e.g. Javascript or Java/Kotlin). Emscripten's FFI features for calling out into Javascript code snippets (even JS snippets that are directly embedded in C/C++ source files) is actually really nice, much better than any other FFI solution I've seen so far (and light years ahead of anything offered by the Android NDK).

In the end the web is just another platform, but a platform that is quite a bit different from the UNIX/Windows duopoly we're used to.