I agree with this article, except for that very last sentence suggesting not using a screen protector at all. I do want to protect my screen from scratches, but spending over 5% of your (very expensive) phone's purchase cost on a screen protector doesn't make much sense. At that point you might as well just accept the ~$200 cost of replacing the screen when it gets scratched.
I've been using film protectors on my S8+. Just yesterday I got my first tempered glass screen protector from Amazon for $10. It came with an ugly glue on the sides which binds the protector to the screen, and is unfortunately quite noticeable. I physically removed most of the glue from the sides, leaving only the glue on the corners, top, and bottom, where the protector binds to the bezel rather than the screen itself. While it's slightly easier for the protector to fall off, it still binds quite reliably, and is worth not looking at an ugly residue on my screen. Surely this beats buying a $50 Zagg screen protector which won't even be compatible with your phone case.