https://root.cern.ch/root/html534/guides/users-guide/CINT.html
I don't quite get the argument:
Because compiling is slow, using a compiler is cumbersome for rapid prototyping when one changes and rebuilds as often as once per minute. An interpreter, on the other hand, is the perfect tool for code that changes often and runs a few times. Most of the time, interpreters are built for scripting languages, such as JavaScript, IDL, or Python. These languages are specifically designed to be interpreted rather than compiled. The advantage of using a normally compiled language is that code can be compiled once the prototype is debugged and refined. CINT is a C++ interpreter, making it a tool for rapid prototyping and scripting in C++.
As rebuilds should compile a lot faster or even instantly, if you don't clean the previous build, but @would definitely knows more about that. I never used ccache etc., I only know it exists.
ccache performance is ultra-high (But no idea how much of an effect that has on a monster build such as Firefox) https://ccache.dev/performance.html
Interesting either way!