The Illinois Supreme Court decided there is no need to claim actual damages. As the article clearly states, there are statutory damages.1 You might think of these as like a fine you pay everytime you violate Illinois privacy law.
1. https://www.eff.org/deeplinks/2019/01/victory-illinois-supre...
Certainly we can be cynical about class actions. Class action lawyers handling cases with millions of class members probably care about individual class members as much as over-compensated Facebook employees care about individual Facebook users (or internet users Facebook spies on in general).
One difference is lawyers are regulated, licensed professionals who have to follow ethics rules, while Facebook employees implementing and deploying privacy-violating technology for profit are under no such restrictions.
Imagine if lawyers could use all the personal, confidential information they see in the course of their work with clients to finance an online "platform" for targeted advertising. Knowing so much about people's personal lives, they could pass on "relevant ads" to clients. Perhaps they could even promise that their services would "always be free". Fortunately, they can't. However, Facebook can.