As @Greybeard wrote, there is more going on than just saving a changed setting. Even if it were only that, it would still be tricky. Different settings take up different size spaces in the file. Trying to overwrite that can easily wreck the file. Early computer based EXIF editors would not do more than report settings for the raw files they would allow users to read. Your Velvia image file may take 2MB more storage than the Provia one, but changing from one to the other seamlessly would be difficult to pull off without a massive amount of processing. All while doing other camera stuff. RAF is vastly different in what it does than JPEG or TIFF or ...
I didn't know about that JPG. But for me it would be handy if the "RAW including that JPG" could be updated. I don't want to bother about editing photos on a computer. I just use the computer for archiving them and I "use" the photos on the tablet where I have my viewing archive.
Digital photography could be so "easy" or "convenient" if all those things were possible. I want the pictures, good pictures. I don't want to bother with software. Sometimes it is a little detail which can make your experience so great, or which can spoil everything.
Yes I used that software years ago with an X100F, but then it stopped working, because the new software no longer worked on my computer (32 vs 64 bit). At the moment I am a Linux user on a 10 year old machine. My most modern "computer" are my phone and tablet.