Agreed, my BUIS never get used and are only on the rifle because I have them and don't feel like selling them or leaving them in my toolbox.
A quality optic will rarely fail and since we are civilians using these in a no pressure situation where no one is shooting back if a battery goes dead or whatever, BUIS really serve no purpose. I like shooting through irons from time to time but I'd never sacrifice putting my optic in it's best position for proper eye relief in order to have BUIS on the rifle.
I've found that my Specter DR has too short of eye relief to mount BUIS behind it so I mount it where it needs to be and don't worry about BUIS. The DR is built like a tank and I can't imagine how it could fail short of running it over with a truck or hitting it with a hammer till it comes off so BUIS really aren't needed with one.
Sorry, can't post pics from my tablet.