Why use frameworks for CMS for Habbo?
I mean, it's more code,
Using a framework means you can avoid writing much of the common code you would otherwise write. "Code on the shoulders of giants" if you will.
Once you know how to use most frameworks it will shave AT LEAST 80% off your development time. This means more motivation and more time to improve the actual project.
Speed decrease... well yes and no. It's another abstraction layer so yes, it will theoretically slow it down.
But many include caching systems that have had countless programmer hours of works into compiling very efficient output. This output is often faster than non-expert (and I mean a true expert) hand written code.
Even if they don't include caching systems, the code is often anything but slow. If you want to prematurely micro optimise everything, write it in assembly.
Either way, programmer time is far more valuable than processor time.
Quite the reverse actually. By using a standard, well established framework, many people already understand the underlying system (and for those that don't, there is usually very good documentation out there. Not to mention places like stackoverflow). The remaining code is smaller, more structured and cleaner.
All of this makes it more supported as a programmer.
As a user it is also easier because these frameworks often handle errors and such in a much more useful manner. This will either point the user in the right direction or give them something more helpful to report (which will also be easier to fix because of what I said above).
And a cms in 4 files? Please learn code again, this is impossible...
Well technically it can be done in 1 file. In fact, both server and website could be one file.