Built-in USB charging ports are a convenient feature for charging on the go. These ports allow you to connect a power bank inside your backpack and charge your devices without needing to fish around for cables. However, these ports don't include built-in batteries, so you'll need to purchase a power bank separately. If you're a commuter or frequent traveler who needs to charge your phone, tablet, or laptop during long trips, this feature can save you from juggling cables.