I've been working on a project using C++ modules in Godot. At some point I was doing a lot of small incremental builds in a single file and they got to be slow, at around 10-15 seconds per recompile.
You're probably thinking "wow 10 seconds is actually really fast to compile c++", it certainly could be a lot worse. For me 10 seconds on this project was pretty inconvenient. I had to recompile very often to tweak small things such as how graphics look, ui adjustments, gameplay values, or other small algorithm changes. With graphics and UI in particular, unlike programming something that is pure math, there isn't really a point where you get it "correct" and the algorithm is completed. To make graphics "correct" requires tweaking it to make it "look good" and "feel good" which are totally arbitrary things that are difficult to get r