What are the pros and cons of putting a screen protector on an iPad Pro with nano glass?

Consider that the optional nano-texture screen is intended to reduce screen reflection and glare from external light sources. By contrast, the standard glass option already benefits from Apple's very effective and robust anti-reflection and hard-coat surface treatments.

Anecdotal reports indicate that while the nano-texture finish is very effective in suppressing reflections, the screen images are slightly softer with less contrast.

Third-party testing of Apple's standard and nano-texture screen has demonstrated that the standard glass is considerably harder and more resistant to scratches and blemishes than the nano-texture finish. The nano-texture finish is much softer than regular glass - and as a consequence is more easily damaged.

Unlike Apple's Studio Monitor (that can also be optionally specified with nano-texture glass) that you are unlikely to habitually touch, an iPad's touch screen is the primary User Interface with the device. Abrasive dust and dirt found in many environments can potentially damage the nano-texture finish when swiping with a finger, or using an Apple Pencil. As such, an iPad Pro with standard glass will likely better withstand the rigours of regular use over time.

Consider that the iPad screen is the single most expensive component of an iPad - whereas a good quality screen protector is a sacrificial layer that is easy and relatively cheap to replace.

Whilst the Apple Pencil has a soft tip that is intended to protect the screen from damage, basic material science tells us that a hard abrasive material (such as grit), will embed in the softer of two materials. Once embedded, the very hard material can be repeatedly dragged across the screen - and cause damage. This risk is obviously of greater concern for the already softer nano-texture finish.

A fingertip can easily “feel” grit an other abrasive contaminants - which you will instinctively not drag across the screen. When using a pencil, you cannot directly feel potentially damaging surface contamination.

As the uppermost glass/air interface is the optical surface is primarily the source of screen reflections, applying any kind of film or Screen Protector over Apple's nano-texture screen would entirely defeat the benefits of reduced screen reflectivity introduced by the nano-texture glass.

Also consider that applying any kind of adhesive product to the nano-texture screen can potentially damage the screen finish.

In summary...

The use of a screen protector is a matter of personal choice. Using a screen protector with the optional (and more expensive) nano-texture screen entirely defeats any benefit derived from nano-texture surface.

Now armed with an understanding of “how” a screen can be damaged - and the relative differences between standard and nano-texture glass and their relative benefits, you should now have sufficient knowledge to help you make an informed decision.

I would think putting a screen protector on the Nano screen would be a little counter productive but haven’t seen any info where it’s an issue if you opt to do it. Most that knew they wanted to use a screen protector seemed to have decided to choose the standard glass instead because you’re either going to put a smooth protector on defeating the purpose of the nano texture or use a textured protector (such as the paper-like options) which…makes you wonder why pay for the nano texture screen just to cover it.