Many people use Linux daily for their servers and cell phones (Android), and a few desktops as well. While many people suggest to use Linux over other operating systems (mainly Windows) for silly reasons like Linux being “more secure” or “more stable” than Windows, I will give the top ten uses for Linux (my opinions, of course).
You can modify the Linux kernel to your specifications.
Run Linux on several different CPU architectures.
Run Linux on small devices (e.g., Raspberry Pi).
Using a variety of free software (most software for Linux is free).
Running web services (like web or e-mail).
Running Linux on very old, out-dated hardware.
Running Linux for cell phones (Android).
Playing with embedded devices (for things such as robots and micro-controllers)