LG addressed the issue with the curved screens not allowing tempered glass screen protectors to be installed... the V30 screen was too curved so it was very difficult to install a tempered glass protector unless you buy the very expensive ones. Starting with the G7 and now V40, the screen portion is flat but the sides have a 2.5d curve just like the iPhone. The glass screen protectors on the V40 typically would have a blacked out border with a little bit of glue on all around it to help stick to the screen. The V40 is flat enough so screen protector installation isn't a problem (unlike Samsung's curved mess) and LG was smart enough to leave a small amount of border space so that you can also use a case with the screen protector and reduce accidental phantom touches that are common on phablet phones.
BTW I got the Mr. Shield brand on Amazon, which has a lifetime warranty so if it ever cracks, send them an email with your Amazon order number and they'll ship you another one free of charge.