Absolutely this. All devices on the market, like that which you suggest, would be reliable enough to be used as one backup location.
However never forget that all storage devices have a finite life so it will fail eventually - as likely that it is that will be many years down the line.
Therefore for good backup practice you should keep at least three copies;
1. The original copy on the PC
2. A backup on a local, external storage device such as External HDD or NAS - ideally kept in a different part of the house (in case of flood/fire)
3. A backup on an online/cloud storage service, such as OneDrive, DropBox, MEGA, etc.
In an ideal world you would also add extra levels to this, keeping previous file versions as well.
At the end of the day, it may seem like a lot of effort - but it will be worth it to stop you from losing precious files such as photos and documents, should the worst happen or you accidentally delete them.
Personally I have around 6TB of data on my PC but only backup around 20GB of that - only my personal photos and documents, priceless memories and important financial information - so check whether you really need 4TB of backup space. Any downloads can always be downloaded again in the future, but you can never take that photo from your holiday again.