Many of the 35mm compacts (viewfinders, rangefinders, early AF) are either semi-automatic or even fully automatic in exposure settings. While we enjoy the compactness of these cameras and their fast and sharp prime lenses, we do encounter their limitness in freedom of exposure settings. Often, we have to rely on changing the film speed to fool the camera meter so that we can achieve the same results as exposure compensation.
However, unlike modern film/digital cameras, many of these classic 35mm compacts have a limited range of ASA/ISO film speeds. For example, Olympus Trip 35 has a range of ASA25-400. While today fine-grain ASA400 negatives can fits a lot of lighting situations, using such film on the Trip 35 will give you no room for negative exposure compensation. If you want a range of -2 to +2 stops of exposure compensation on the Trip 35, you need to use ASA100 film.
So, in other words, what film speed to use depends not just on the lighting situations but also on the range of exposure compensation that you would like to perform.