In case of IROPS, QR is ok when dealing with QR-issued tickets for QR-operated flights. There are plenty of mishaps described on this forum, and plenty of us have been burned by QR at one point or another... but they can also be good. Any situation that involves another party (be it another carrier, or a TA,...) is far more likely to result in a bad outcome. So there is a bit of risk associated with that. We're talking ~€800; not an insignificant amount.
Years ago I was unable to UG a QF-issued ticket; in DOH I was told that they couldn't process upgrades for tix that was not issued by QR. I don't know if that's still the case, but it points to a similar theme of QR not exerting control over the ticket.