You are narrating events by telling what happened a Lego block at a time.
Dialogue is more interesting and vivid than summarized conversations.
Dialogue also helps signal the more important or dramatic moments of your narrative. As with description, it's also possible to overuse dialogue. Listen to how people speak. Eavesdrop a little and try to write down some conversations. What you'll find is that people usually don't speak in long, well-developed sentences.