In my opinion, that's not a valid argument. If you move further away, they'll appear identical, but the 27" is now going to also appear smaller, like a 24". PPI is not a way to measure how sharp something looks. For instance, a 100" 1080p screen, from a distance of 10 feet, is going to show more detail (more detail to our brains translates to sharper) than it would on a 50" 1080p screen 10 feet away. People make a similar argument using a smartphones PPI, to determine how much better it is compared to X phone, I find it ridiculous, but that's just me.