Same with Bluetooth, Qt and every other piece of janky garbage that works just well enough to survive, but badly enough that every single person on the planet hates it.
[1] This is obviously hyperbole, before anyone gets "HN literal" in the replies.
On paper, it's great because it does everything and is cross-platform. In practice, though, including it with your product will introduce dozens upon dozens of completely preventable bugs and all kinds of bizarreness that will suck you away from solving the actual problems necessary to releasing your app.
The quirks in Qt are coming form the fact that was trying and still tries to implement a sane C++ dialect and build system (qmake) in a time where the standardization efforts of C++ and event STL was not at the same level of today. For example So now we Boost for signal and slots. Do we still need moc? The same for collections, maps etc. When they go introduced there was no standard / portable solution.
You can probably describe Qt like the C++ equivalent of the java promise (write once - compile everywhere) with its own support for sockets, filesystem and what else abstraction you can imagine off.
Qt was an impressive feat for its time and a joy to program for. Much better than what the web was at the time with is amalgam of languages and text only interfaces. It took web and flexbox up to 2015 to be able to implement the holy grail layout https://en.wikipedia.org/wiki/Holy_grail_(web_design) .