Having root permissions on a KaiOS or Android device means being able to access all those functions that only the manufacturers of the device can access using the command line, and therefore ADB. These privileges depend on binary files present within multiple partitions. Having access to at least one of these really means a lot. You can get root as the default in the firmware (Boot partition) or perform backups and restores in case of damage (Recovery), or get both of these possibilities starting from the user space (using applications).
Getting root privileges is not risky for the device, but the use you make of it can be!