Here's a thread where helpful experts here said that it
likely doesn't offer any protection against breakage of the glass substrate, i.e., no real cushioning against screen breakage like it would provide on a cell phone screen.
That only leaves scratches and scuffs. My screen protector was so reflective that I couldn't stand it anymore and removed it. It was the clear type. The matte type should be a little less transparent, and in that case, you have to ask yourself if you want to have even a slightly less clear screen.
I now have migrated to a combination of a carrying case like a sleeve where I can easily extract the reader and use it naked, and careful handling.