Like object to object matching, object-to-picture matching has some very important benefits for toddlers. One, it again helps with vocabulary, moving from left-to-right and providing order. However, object-to-picture matching also helps toddlers to explore abstraction.
In other words, it helps toddlers start to make the connection that what they hold in their hand is the same as what they see on the picture. The picture of an apple is an apple, and the apple they are holding is an apple. This sort of abstract thinking is essential for reading. And, this work easily helps toddlers make those connections.