for security updates, IMO.
iOS 12 is great. Very fast, very stable. There aren't really that many must have features each year now, but there are always small improvements, and iOS 12 is so fast that I can't see any compelling reason NOT to update (possible exception: multitasking on iPad was way better on iOS 10. I really can't stand what they've done to it since).
I'm sorry that I was less appealed to you guy's opinions. I also respect other's ideas too! Thanks for all replies