The multi-state settlement was a huge loss for Meta.

You are focusing on the money, which is not the important part. The important part is that the settlement just settled that one lawsuit. There are many thousands of individual lawsuits over many of the same issues, mostly by local governments (school districts).

Almost all the work the nearly 50 states in the multi-state lawsuit put in to prepare their case, such as depositions, getting expert reports, their successful legal arguments, the testimony from the trial, etc can be used by the plaintiffs in all those other suits.

This basically gives all those plaintiffs a fully loaded giant legal cannon that was custom built using the vast resources of the Attorney General's offices of almost 50 states specifically as an anti-Meta weapon.