Hey wdbro.
Basically, you are correct, but so is @Captain_WD (he’s not available today, so that’s why I’ve
stepped in 
). You can use a WD Purple drive as a regular secondary storage drive if you have one lying around and I’ve seen lots of cases where this has been done without any issues at all. However, as @Captain_WD has mentioned - it’s not recommended that this is your choice if you go for a secondary storage drive, because of the different firmware used for the WD Purple HDDs. Having in mind that said firmware has for that kind of usage (having in mind ATA streaming commands), you should know that the idea behind that type of commands is that in these cases, keeping the write rate is prioritized instead of having every single byte of data in a perfect condition. This is OK and it might not even be noticeable if it ever happens with a video (especially having in mind WD Purple’s optimization for video surveillance usage with high quality results). Basically that means that the device will transfer the requested amount of data from the host within the time specified, even if an error occurs. So for other type of usage, this could result in a corrupted file, while in video streaming, you won’t lose the constant write flow and thus lose the whole video and the end result will be a full video file.
Hope that clarifies things a bit.
CK_WD
