Rescue breaths matter significantly more for children than for adults, and the reason comes down to why they’ve gone into arrest. In children, cardiac arrest is most commonly caused by an airway problem either choking, respiratory failure via drowning etc, rather than a primary cardiac event. Rescue breaths can force an obstructing object further down into one bronchus, freeing the other lung to function at 50% capacity. For adults, the primary cause of cardiac arrest is cardiac, so good chest compressions take priority. If there is hesitation around rescue breaths for adults due to hygiene concerns, compressions alone are significantly better than nothing.
