Difference is mainly in software it comes with and I guess build quality. If you need simple backup solution and don't need encryption, there is absolutely no issue in just option for a basic passport drive.
Based on @Ankur003 advice, I have started using WD SmartWare software to automatically backup data from my internal drive to external 4TB WD My Book. This software will only update files which have been added or modified, ensuring that in case of data corruption, I don’t accidently overwrite good files with bad ones during manual backup. Plus the software stores data in native format, so I don’t have rely on it for restoration.
I am also running an internal backup every evening from primary data drive to internal backup drive with built in backup software of Windows 7 and after every shoot, I manually backup data on couple of other drives I have for further safety.
Unlimited Photos Plan (free 3-month trial, then $11.99 per year—equivalent of less than $1 per month): Store an infinite number of photos in Cloud Drive without worrying about taking up space on phones, cameras, or other devices. Customers can upload existing collections and store all future photos taken. This plan also includes 5 GB of additional storage for videos or other documents and files.