The convenience of the MOC is its raison d'être. The minor pain point for me is practically being forced to use the Qt Creator IDE. I'm happy to see a possible best of both worlds solution like this.
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.