Convenience
Disposables are ready out of the box. Pod systems need you to fill pods with e-liquid and replace pods or coils from time to time.
Cost over time
A pod system costs more up front, but e-liquid bottles and replacement pods are usually cheaper per day than buying new disposables, especially for regular users.
Flavor and strength choice
With a pod system you can switch between any compatible e-liquid and nicotine strength. Disposables lock you into one flavor per device.
Less waste
Refillable devices are reused for months, which means fewer batteries thrown away.