My goal with the transpiler is not only the transpiler, although my front end had to be created differently of an normal compiler and preserve more tokens that could be discarded during the compilation. This also can be useful for a tool that does refactoring.. like renaming variables etc.. so in any case it it useful.

The new C23 language has a lot of features that makes your code not compile in previous C versions like attributes digit separators etc.. Someone may wants to create a new project in C23 and soon regret because the users of the code may need C99. This would be one use case, you can create a C23 code and have C99 versions of the same base code.

Unfortunately my transpiler is not "production ready" yet and I don't have IDE plugins etc.. that is required to make the tool more productive.

The other advantage, if we had a production ready transpiler with a IDE support etc.. it that we could use C23 and compile to C99 without having to wait for compilers like msvc to implements the standards.

Also some experimental features (like defer) can be used and you can distribute your code in standard C99. We have more freedom to use wherever we want and distribute a "readable" C99 code.

By the way most of the C transpilers or compilers generates C code only for immediate compilation. CFront was like that.

My transpiler have two modes one is for direct compilation and other is to distribute generated code.

Each mode has advantages and disadvantages.