Controllers on motherboards can be a little rubbish. A fan controller allows individual control over fans, which can help vastly improve the air flow. As you can test different speeds until the fans are all working in unison, you can create profiles at a variety of different speeds, which is...
Not a bad idea for checking some basic info when building your own ports, or quickly looking at kernel, power usage that kind of stuff. The Android versions provided by many telco providers are often out of date (at least in this neck of the woods) and provide little in the way of hardware info...