Qt Creator doesn't even get involved in the build once it has started qmake - a qmake .pro[ject] file is nothing like a Visual Studio project file. You are supposed to make edits other than adding or removing source files by hand. So you really don't need Qt Creator for moc.

Note that qmake is generally easiest for tiny programs such as bug reproducers. For anything nontrivial, it's better to use CMake. Most advanced functionality in qmake is undocumented and weird. Qt itself is moving to CMake with Qt 6.

I was trying to figure out how to do MOC from gnu make when I came across this, the only other option I saw was to run qmake and then run that generated makefile from my makefile. Of those two options verdigris seemed to be the better choice to me.