Hey there, Acronis!
Mattios is right. WD Purple HDDs are strictly designed for surveillance use. They are tested to be compatible in wide-range of security systems. They can be used 24/7 always on high-definition surveillance environment. These are all features, you will not be able to notice if you are using it as a desktop drive. The speed and the spin-down might affect your computer's performance.
The WD Red is basically the same thing. Even though the speed would be better, you won't be able to experience all its advantages because it's a NAS/RAID drive with specific features that can't be noticed if it's working as a standalone drive on your PC.
We have WD Greens for massive secondary storage solutions. I'm not sure what is the bad reputation about those. People often get disappointed with them because most of them are not aware of its purpose, i.e. using it as an OS drive or for gaming.
HDDs are very sensitive, thus every drive is highly likely to fail at some point of time. That's why it's recommended to always have a backup of your data on more than 1 location (preferably both on-site and off-site).
Hope I was helpful. Let me know if you have more questions!
SuperSoph_WD