Flexible PCBs have some very amazing benefits including:

Reduced space and weight: Most of the advantages associated with flexible PCBs come from their small volume and weight. In fact, the use of flexible PCBs can reduce space by more than 50% and reduce weight by more than 95% while maintaining the function and reliability of the circuit.
Durability: The flexibility of the PCB, the reduced weight and the reduced number of interconnections enable them to handle changing external forces and improve their ability to resist shock and vibration.
Signal integrity: Flexible PCBs can work in a variety of environments and their signals will always run smoothly regardless of external conditions, which proves the signal reliability of the PCB.
Higher density: thin layers and smaller components mean flexible PCBs can support higher circuit density.
Minimize error: Flexible PCB reduces wiring errors due to the elimination of mechanical connectors and small options in assembly methods.
Low cost: Because flexible PCBs manufacturing involves fewer assembly steps, they tend to be relatively inexpensive.
Heat dissipation: The thinner material of the flexible PCB allows for a larger surface area and volumetric ratio, thus improving heat dissipation.