Series has many benefits over a traditional smart campaign, including;

• Series enables you to create multiple paths and diverging/converging paths for each messaging flow. Campaigns on the other hand only allow linear paths.
• Series gives you a birds eye view of the entire messaging journey of your users, something that isn’t possible in Campaigns.
• Series allows you to use all outbound channels, including Custom Bots, Mobile Carousels and Product Tours.
• Series allows you to create fallbacks, in the event users don’t match rules for different messages by enabling you to create diverging and converging paths.
• Series can target users, leads and visitors, Campaigns aren’t able to target visitors.

You can read more about Series in this article.