Are there any concerns/risks to using Watchtower?

Someone recommended it for keeping my containers up to date automatically. I checked out the repo and it seems too good to be true. It just updates your containers when a new image is available and everything just works out of the box? I'm a bit scared of just leaving it alone in case it might break something. The fact that it doesn't come with a gui also scares me a bit.

Does anyone here use it and can recommend it? Any horror stories?