The problem is that Qt and other cross-platform frameworks tend to look glitchy, as in their differences are non-intentional and jarring.
They also tend to just look pretty old-fashioned, because these frameworks are pretty old now and the controls, layouts, and workflows they provide are a bit old-fashioned.
So the first impression you get for software using Qt is old and glitchy. Which isn't great.
honest question, is that the impression you get from using the Blizzard launcher (https://media.mmo-champion.com/images/news/2013/june/launche...) or stuff like Substance ? (https://www.awn.com/sites/default/files/image/featured/10157...)
I just finally got switched to Windows 10 on my work computer. Every time I start up a simple calculator, it takes up most of the space on my gigantic 27" QHD screen! Do they think I'm blind or something? The old Windows 7 calculator looked just fine and was an appropriate size.
I think people tend to assume that software that looks old-fashioned is likely to be unmaintained or buggy.