The usefulness is debatable at least on windows, It’s not very common for end users to have a compiler installed so 98% of the users likely won’t be able to make use of it. (unless addon authors start to demand end users install a compiler, which would be “strange”)
The argument for “I’d be handy to have for packaging” not sure I’d recommend packaging with our distro, the official python distro would probably be advisable there.
On the other hand it’s only ~200k added to our distro size, and we’d become ever so slightly more compatible with mainline python, i’d say why not? but it’s ultimately up to the python module to decide.
Indeed it is debatable. And yes most users won’t have a compiler. In fact python packages are expected/encouraged to provide bianry wheels when some compilation is needed. For example OTIO won’t need the Python headers that would ship in Blender. OTIO will pre-compile and ship the package as wheels so that all users can just install the package.
I totally agree with this. Blender’s Python shouldn’t be used to ship wheels. But that makes me realize that maybe having the headers could encourage users to use Blender’s Python to ship wheels to PyPI. Though I don’t know the Blender community enough to know if that is a concern or not.
How about making this a CMake build option to install Python headers? Then people who are already building Blender from source can easily build 3rd party Python modules too.