First invocation may be. Subsequent builds are very fast, unless someone decided to write random bullshit into the build scripts that execute at config time, making the config process impure.
I’m mostly thinking of Android projects. If I have time I’ll try some speed tests with a new basic project. But I don’t think I’ve even once done something in Android Studio and thought “huh, that was surprisingly fast”. Maybe some of the hot reloading stuff is okay (when it actually works).