It's just like your computer and IDE, you start it up and never shut it down again.
Wouldn't it taking the whole afternoon be because it's downloading and installing assets, creating caches, indexing, etc?
Like with IDEs, it really doesn't matter much once they're up and running, and the performance of the product has ultimately little to do with the tools used in making them. Poorly optimized games have the reputation of being poorly optimized, that's rarely down to the engine. Maybe the complete package, where it's too easy to just use and plop down assets from the internets without tweaking for performance or having a performance budget per scene.
No, it is not. You don't have to restart your computer/IDE every time you compile a project. With UE5, you nearly always do need to restart the editor.
Wouldn't it taking the whole afternoon be because it's downloading and installing assets, creating caches, indexing, etc?
Like with IDEs, it really doesn't matter much once they're up and running, and the performance of the product has ultimately little to do with the tools used in making them. Poorly optimized games have the reputation of being poorly optimized, that's rarely down to the engine. Maybe the complete package, where it's too easy to just use and plop down assets from the internets without tweaking for performance or having a performance budget per scene.