Indeed, it is a simple reminder, but we have grown to trust our 'magic bracelets'. I don't think it's meant to replace common sense and reason when it comes to scrubber time. The good thing; a warning at -1hr and alarm -30min, even if it's not factual, will drive the point home better than just a mental reminder. "...I've set up this timer, am I going to ignore it now?"
Yup, I like it too, and use it. The same way I like a physical printed checklist. It's easy to get distracted and forget stack time, this is a good thing.
I was just making the point that you need to understand what it really represents - there was some suggesting early in the thread that a few minutes added or subtracted from the stack time was a precise thing that needed to be accounted for so that you would get exactly the right amount of time that you were owed from the scrubber. I don't think that is really how it works...