The main benefits will be better usability, cleaner interface,
compatibility with any window manager and desktop environment. It does
not depend on kdelibs since it is a pure qt application and thus it will
be very lightweight.
The gtk3 front-end, on the other hand, breaks many window managers since
it uses client side decorations and it breaks many existing themes with
every gtk version. I tried it with openbox and IMO it looks terrible
with big window borders, toolbar buttons mixed with window buttons, etc.
making it not very usable.
The change is not a big deal, the debian files would generate an
additional package (gimagereader-qt) and people happy with gtk3
front-end would install gimagereader-gtk :)
I found that it needs a small patch to compile in Stretch, maybe not
necessary in Sid...
Index: gimagereader-3.2.99/qt/src/hocr/HOCROdtExporter.cc
===================================================================
--- gimagereader-3.2.99.orig/qt/src/hocr/HOCROdtExporter.cc
+++ gimagereader-3.2.99/qt/src/hocr/HOCROdtExporter.cc
@@ -26,6 +26,7 @@
#include "SourceManager.hh"
#include "Utils.hh"
+#include <QUrl>
#include <QDesktopServices>
#include <QFileInfo>
#include <QMessageBox>
Index: gimagereader-3.2.99/qt/src/hocr/HOCRTextExporter.cc
===================================================================
--- gimagereader-3.2.99.orig/qt/src/hocr/HOCRTextExporter.cc
+++ gimagereader-3.2.99/qt/src/hocr/HOCRTextExporter.cc
@@ -24,6 +24,7 @@
#include "FileDialogs.hh"
#include "SourceManager.hh"
+#include <QUrl>
#include <QDesktopServices>
#include <QFileInfo>
#include <QMessageBox>
