As always, that depends entirely on the situation. If you live in a country with temperatures north of 30°C in the summer and without air conditioning, you want to ensure your Mac is not running at unnecessary high temperatures. In this case, a fan control app will do the job. Personally, I use TG Pro to up the fan speed of my Mac Mini from 1.800 RPM to 2.500 RPM. It's not audible for me because I listen to music all day while working. So why let the Mini run at a higher temperature? Because Apple is obsessed with silently operating devices?