The Onion Omega is a modular microcomputer. You snap together the chip, a “dock”, and as many expansion boards as you need to provide extra functions.
You could make an Omega that works like popular single board computers by mounting the chip on an “expansion dock” that adds the inputs and outputs to connect it to sensors and actuators. If you need a PWM controller, an Ethernet connection, or a small screen, there are expansion boards that will stack atop the dock to add those features. If all you need is the wifi enabled processor, there’s a mini dock that just provides power, a USB jack, and nothing else. With Onion Omega, you snap together just the components you need.
The Omega chip comes pre-loaded with Linux for a quick out-of-box experience.