It works. The iPad Pro is a powerful device and can be used as a main machine for many users, so if you want privacy, this will do the job. However, I don't really like the product too much - it's easy enough to put on, but the sharpness of the screen is affected. Given the iPad Pro has such a great screen, and you pay a lot of money for it, the privacy screen is a step back unless you really really need the privacy. The screen also increases battery drain as the screen tries to amp up to overcome the screen's darkening effect.
Personally, I find the Paperlike screen cover better - useless for privacy, but makes the stylus more natural in use.