Is bacterial pneumonia more dangerous for children?

Yes. Bacterial pneumonia is more dangerous in the extremes of age - the very young and the very old. Their immune systems are sometimes not capable of fighting off the infection on their own and therefore should be treated appropriately in consultation with your doctor. For complicated/difficult cases in children, it may require the expertise of a pediatric pulmonologist to guide therapy.
It can be. Very young children or those with underlying severe chronic diseases are more at risk for complications and even death than older children or adults. The same applies to patients at the other end of the age spectrum, that is the elderly. Pneumona is usually treatable with antibiotics and support however.