WD Purple Vs Enterprise SATA/SAS Drives And RAID 5,6,10,50,60

The red drives are designed for mass storage.  From the manufacturer:

WD's exclusive NASware technology, built into every WD Red hard drive, improves NAS storage performance by reducing common hard drive concerns in NAS systems including concerns for things like compatibility, integration, upgradeability, reliability and cost of ownership that are experienced with a hard drive designed for desktop computers.

In theory the red drives support higher temperatures common with being in a chassis close together and some run at 7200RPM.  However, whether there is any actual benefit is something you would have to test.  It is really down to questioning what the manufacturer says.  I can say I have never had a red drive fail in an array in the last 3 years since using them in QNAP arrays.  I have not used purple.

As far as the Seagate side of the question goes, we have two types of consumer drives which support 8+ bay enclosures:

The IronWolf Pro, which is engineered for NAS use, and the SkyHawk, which is engineered for surveillance use. As you mentioned, some of the features like higher MTBF and RV sensors which separate them from regular desktop drives are similar, however the use-case for the drives is very different, similar to how a road bike and a mountain bike are made up of mostly the same actual components, however they are engineered and fine-tuned for a specific use which makes them different.

The firmware on the IronWolf Pro (AgileArray) makes it ideal for balanced read-write workloads, multiple users hitting the NAS at the same time, networking, etc. The goal of a NAS-engineered drive is to always be up and running and keep performance of the array snappy. The standard IronWolf is similar in a lot of ways but supports 1-8 bay enclosures.

The firmware on the SkyHawk (ImagePerfect) is ideal for write-heavy uses, like CCTV, DVRs, and NVRs. The firmware "thinks" in this way so as to manage massive streams of highly detailed video recording as it comes in to prioritize video quality and reduce dropped frames. We recently came out with a 10TB model of SkyHawk engineered for AI use to manage 16 AI streams / 8 AI channels.

We see topics happening in online communities all the time about what "actually" makes different branded hard drives better or worse for certain things, beyond the marketing and pricing differences. Some want to know why an enterprise rated drive is actually better than a desktop one, some want to know like yourself why an enterprise label drive is different from one branded for NAS or surveillance, and firmware, while it isn't the only consideration, plays a big role in the matter. It effects how the drive operates, what it prioritizes, how long a drive in a RAID array tries to correct for errors versus the controller passing it on to another drive in the array for performance considerations, how it allocates its resources, etc.

If anyone is interested in the differences between desktop drives and more robust purpose-built ones like NAS drives, here is an interesting article from Storage Review on the topic.

Don't use disk.  Use tape drives.  If you want I have a friend that works for HP and is MS in Computer science from UOP.

Define an idiot.  Keep doing the same thing over and over again and expecting different results.