This is a great question. Here are some of the positive points of Suetonius' account.
First, he was a governmental official. He held the position of ab epistulis, which was one of the highest positions of the Roman Empire. So, he had access to all the government documents, which shows in his work. Second, he was a personal friend of Pliny and Pliny states that he was a very studious person, which also shows in his writings. The details that he includes are insightful and meticulous. Third, when we use Suetonius' accounts in comparison to the historian of the time, such as Tacitus, then we can gain another valuable perspective. All of these points are true benefits.
The cons of using Suetonius are the same with any author. All authors have their own blind spots and biases.