The raspberry pi pico breakout board enables you to use the raspberry pico without having to use a breadboard. The pin headers give you access to the raspberry pi pico pins which can facilitate debugging , making connections using dupont cables and making more permanent connections while keeping the pico board intact. There is also a reset switch that you can use to reset the raspberry pi pico.
Project site where the design files and schematic can be found:
Official Raspberry Pi Pico Pin Wiring and Usage: