AIO boards typically combine the functions of a flight controller, video transmitter, and power distribution board into a single package, which can be more convenient and easier to install than using separate components. They may also include additional features such as a built-in receiver, voltage and current monitoring, and overcurrent protection.
AIO boards are widely used in FPV drones due to their compact size and versatility. They are often preferred by users who want a more streamlined and simplified setup for their drone, as they can reduce the number of components and wiring required. However, AIO boards may not offer the same level of customization or flexibility as using separate components, and may not be suitable for advanced users or more complex applications.