While WinSQL does not offer direct support for InterSystems products, out of the box, and as far as I know, no plugins exist. I would recommend switching to something with better support, e.g. Datagrip or DBeaver.

Or if it's required using WinSQL, you may write a plugin for it or order it (I can help with it), which will offer better support.

When the google group was quite active, years ago, I did some analytics as well, and as I remember, there were quite similar numbers as well. And we had a dedicated Russian forum and had just about 10 active people there.

My suggestion is, that, Developers on InterSystems technologies are not used to using the Internet for their issues. They probably may ask colleagues by company, but not the Internet. As you would see on StackOverflow, there is a huge amount of questions and answers on any language and technology. And even so, we have jokes, that some developers write code by copy-pasting code from StackOverflow. But apparently, it's not the case with ObjectScript and IRIS. And we have just a few questions per year on StackOverflow and only a couple or so people who would answer there.

So, I think, InterSystems developers mostly prefer to solve issues on their own. And this is a main issue as well. Because they may miss some new features that appeared in the technology, some useful projects or technics.

And I'm sure that, any involved developer should be part of spreading the importance of using DC amongst his colleagues and encourage them of using it, at least to read articles. 

Yeah, actually, in several projects I've used %CSP.REST to process the whole application. Static web files and REST itself. And the main cause to do so is that the internal webserver did not accept index.html as default index. So, it required to putting it manually to the URL, or using %CSP.REST, which work with static files, and correctly processes index.html. And it requires just one Web Application configured. But in case, when an application is partly anonymous, requires more attention to security.

Any reasons for doing this? This is not how it is supposed to be. REST should answer with Status 401, and optionally  with methods available. And web application when gets 401, it knows that it has to authorize the user, and shows its own page or initiates SSO, depending on the task.

Anyway, if really do this way, It looks like %CSP.REST extends %CSP.Login, and it has Method Login

Called for a REST page in the event of a login being required

Did not test it, but I would expect it will do what requested