I was also disappointed that this isn't included in the browsers given that it was designed to be very simple to parse and compile. So I tried as an exercise to build such a compiler[0] and indeed it was much easier than I expected (with a few shortcuts of course, being a POC). It is just 5kb gzipped and it compiles to binary most of the WAT code out there and also quite fast, just a few ms. That said, I think writing WAT by hand is only helpful for very small critical hot code, anything more complex and IMO you need an abstraction of some sort.
You can inline the binary as base64 or simply a Uint8Array and instantiate it without having to fetch a wasm file. Many choose that approach as it also makes the library `import`-able in sync. The code I was pointing can be used to compile the WebAssembly Text format to binary and instantiate it afterwards on-the-fly, which is useful if you don't want a build step, so skipping the tooling(outside the browser) and also make edits which will then be compiled directly when the file executes. It's an option for experimentation mostly.
Yes, my point was that it's so trivial (and negligible in byte count size) to implement a compiler for the Webassembly text format, as the POC demonstrates, that it's curious why the browser isn't including one so that there isn't the need for extra tooling.
[0]: https://github.com/stagas/wel