Films are unnecessary for the Samsung Xcover per se, because the device Gorilla glass has, which is very scratch resistant. However, if you do not feel like fingerprints on the glass has, the film you can grow quiet. I've done it for an hour without a sole speck of dust. However, the sensitivity of the touch screen will be compromised. Not much but a little.
Therefore, it is okay. But not necessary. Now the grease stains are flat on the slide ...