I played rugby, and now I coach kids (including mine).
Rugby tackling is safer because (1) no pads or helmets, (2) hitting with the head (spearing) is a penalty, and (3) all tackles must include an attempt to wrap with the arms (thus, a pure “hit” is a penalty).
My observation is that while rugby has the expected number of scrapes, broken noses (a personal occurrence!), sprained joints, etc., rugby does not seem to experience the VERY serious injuries anywhere nearly as frequently as football.
My daughter’s boyfriend (at the time) lost his appointment to West Point due to concussion damage in rugby.