Hello David, thanks for your feedback. I believe that the answer to most of your concerns/questions related to other projects that would benefit out of something like this is already answered by me in the RFC. I mentioned major PHP projects that will directly benefit out of something like this.
About the demand, well, that is also being written in the RFC. Regarding the question in StackOverflow, was just mentioned to expose the "demand" of validating a json string, and is one of the most ranked questions, is in the top 10 of questions with php && json tags. I believe that such a thing is talking by iself. Providing real use cases wont make a difference, because the number of examples are infinite honestly. Yes there are userland packages that can do this for us, but in big products on big companies, relying on 3rd party packages is not always cool, I have being experiencing that in my company actually. Regarding examples of raising issues ... there are a LOT in github, and the only possible solution is always to increase the memory limit or use a 3rd party package (which as I said, is not always suitable). But ... lets be objective, or try to be at least ... PHP has a parser already, this functionality is just allowing us to use it without the need to consume memory. I see it useful, actually, this RFC is the result of a real need we have in my current company at the moment, and after digging around the internet I found hat we were not the only ones. Thanks for taking our time on this, I appreciate it.