To avoid the unnecessary notification of passersby that I have just unlocked the car, it's always been my custom in Prius to use the inside lock button as I'm getting out. I was surprised that Kona wouldn't allow this. It turns out that it is more cautious about determining whether your key is still in the vehicle. Step fully out and you're good to go.
I like to use the button on the handle to lock or unlock. I don't know if this is safer than using the fob, but my inclination is that it is, and won't broadcast your cars door code so that crooks can pick it up, but I am not sure. I have heard stories of people using their fobs and crooks picking up the code entering their cars.
I'm not sure the button is much safer as the Kona is aware of the key's presence around the car. This suggests that the fob might be communicating with the car at this point.