As your son listens and follows along, precious reading readiness skills are being practiced. Listening, attention span is increasing. Comprehension is practiced s you stop to discuss the story. Left to right progression as the pages turn and you read the sentences. Observation and comparison of details in illustrations.
Page numbers mean something.
The author writes the book. The illustrator draws the pictures. The name of the book is the title. Most important is the time you are spending with your child. If you are rushing to get through the books, you are sending a negative message about reading and are probably doing more harm than good.