Haha my girlfriend wasn't even crazy about my idea to timer PWM our aquariums LED light
I can understand concerns like that; just because humans are not particularly sensitive to 500Hz flicker doesn't mean other creatures aren't also.
Because this doesn't control anything, rather tells you information, in my eyes you are still better of with this thing rather than not knowing this info at all.
But presumably, you are going to base decisions on the presented information, so if the information is incorrect because of a programming error, you're still in the same situation as if you'd put the computer in the driving seat.