I'm not sure I understand your example. Emacs integrates, it doesn't need to be integrated. It also has the best git interface I have ever seen (magit).
In a certain sense a subclass of Emacs users are the makers since it is a traditional Free Software model not backed by a major corporation. But that can be seen as an advantage since there is no single point of failure, and if GNU doesn't do a good job it can be forked, and has in the past (remember XEmacs?).
Practically speaking, the major disadvantage of Emacs is poor asynchronous/ multithreaded support. That's not an easy problem to solve but I do think it will get better eventually, and I don't find it a major impediment in day-to-day use.
Well, if you want a clear example of what I mean, Jetbrains makes a plugin for Kotlin for their IDE and another one for Eclipse. They don't make one for Emacs. The Emacs community has to make it (maybe they do, I don't know).
Look at any tool (except for GNU or Lisp stuff) and try to see how many of them have Emacs plugins made directly by the tool authors.
Eclipse, Visual Studio Code, Atom, etc., tend to have plugins made directly by the tool authors, in many cases.
In a certain sense a subclass of Emacs users are the makers since it is a traditional Free Software model not backed by a major corporation. But that can be seen as an advantage since there is no single point of failure, and if GNU doesn't do a good job it can be forked, and has in the past (remember XEmacs?).
Practically speaking, the major disadvantage of Emacs is poor asynchronous/ multithreaded support. That's not an easy problem to solve but I do think it will get better eventually, and I don't find it a major impediment in day-to-day use.