Just in the spirit of discussion – it strikes me that attached signal handlers are indeed an advanced concept, but constructors are not: constructors are something that most modern programming languages have.
And for this reason – they are something that one goes looking for! I had to hunt quite hard to find this method of “constructor definition”, and (in another thread ) I still haven’t found one for scene/level “construction”.
So IMHO it would be quite natural to tell programmers about the existence of contructors in QML: not under the heading of “Advanced QML concepts”, but rather under the heading of “basic language concepts you’ll go looking for” 😉
Just entirely IMHO, of course