So I suppose you never use a browser to run a web application on the desktop :thinking_face: Anyway it;s a client server architecture designed for remote installation on servers as well as local installations. It makes sense to have one installer do both.
As to the old installer, when you knew about the un-obvious features, it was brilliant from a user perspective, but I'm willing to bet that from a developer perspective, it was hard to maintain, hard to add new features to, and fragile.
The Pragmatic Programmer, Your Journey to Mastery and Agile Software Development, Principles, Patterns, and Practices are both books I found very helpful.