Not op, but I have one of these devices and the battery life is amazing. I've had it for over a year and only had to recharge it once (and I did it a year ago because I was going on a trip and did not want to risk having to recharge it). I don't use it everyday now, but before my first charge, I'd say I'd turn about 15 pages a day 5 days a week.
In terms of the e-reader battery, it doesn't change anything as it's the equivalent of turning the pages with your finger.
Oh, thanks for the update!
I think you misunderstood how it works, though: it does not literally move, and it does not have a motor. It works by having a sensor on the clip that simulates a finger tap via an electrical signal.
That makes it hugely more appealing, thanks for the clarification!
Can I ask: you use it on a kobo with a recessed screen? It works if the screen isn't completely flush?
It is normally available on Amazon with reviews and returns, but I checked now and it's currently unavailable in Amazon US
Do you have a link to the item on amazon so I can set up a watch? Can't find it through the Amazon search, or google.
Edit: NM, found the link. I'll set up an alert if it comes back in stock, thanks again! https://www.amazon.com/SYUKUYU-Control-Reading-Surface-Android/dp/B08T8CZYF3