It is just beyond experimental now, and finally in the early adopter phase. Those early adopters are trying things are trying to develop best practices - which is to say as always: they will be trying things that future us will laugh at how stupid it was to do.

There are still some features that are missing from compilers, but enough is there that you can target all 3 major compilers and still get most of modules and benefit from them. However if you do this remember you are an early adopter and you need to be prepared to figure out the right way to do things - including fixing things that you get wrong once you figure out what is right.

Also, if you are writing a library you cannot benefit from modules unless you are willing to force all your consumers to adopt modules. This is not reasonable for major libraries used by many so they will be waiting until more projects adopt modules.

Still modules need early adopters and they show great promise. If you write C++ you should spend a little time playing with them in your current project even if you can't commit anything.