Do you have any tool that you use all the time? Do you recommend it to everyone unprompted? Is it ridiculously specific to your situation, wants and needs? Let every one know how they can make their sewing better!!
I myself don’t have any at the moment, but I have been eyeing a nice pair of left-handed fabrid scissors for quite some time and I might get it some day.
I think the biggest risk with rotary cutters is forgetting to switch on the safety cover when not in use. Otherwise, I’d say the safety risk is the same as scissors: always be mindful of where your fingers are when cutting.