Although they both are storage devices, there are multiple differences between them. NAS has much more storage space than an external hard drive.
Depending on the number of drive bays a NAS has, they can store multiple drives. Also, the storage of NAS can be upgraded according to the user’s needs.
NAS comes with RAID configuration, which is not present in external drives. If an external drive malfunctions or fails, you will lose the data along with it. RAID is a failsafe feature that backs up any data you store on the NAS. This means your data will always be safe even if any of the drives in a NAS fails.
In order to access external hard drives, it needs to be connected to a PC via cables. NAS can be accessed by any mobile device over a network.
Furthermore, media content can be streamed to any device using NAS, something that cannot be done using an external hard drive.