kivy语言繁琐，背后的理由

Kivy has this kv language to define the UI , the definition file can become quite complex , There is a kv designer package on github which automates the generation of kv files but is quite buggy and unreliable. So the question is why does kivy want the programmer to manually write those UI definitions like even hardcode the positions and dimensions of UI widgets. Most other libraries like QT, VB etc have a UI designer as the core feature but Kivy did not start with it and expects programmers to hardcode it , I find it pretty cumbersome although I feel I am missing something. Or is it that it is only I who find a steep learning curve for kv language and I don't know about some tools which help in writing kv files. to define the UI , th