It is designed to help prevent websites from tracking you, and it is also designed to block ads to a certain degree. However according to the folks at XDA, it has been discovered that a new ticket on Mozilla’s bug tracking platform, Bugzilla, it appears that full-on ad blocking will be a feature in the Firefox Focus 9.0 update.
Previously Firefox Focus would block ads that had trackers attached to them, but with Firefox Focus 9.0, it seems that all ads will be blocked where one of the goals of introducing the feature is to improve on loading times. The feature is expected to only roll out to about 50% of users first to see how it affects the usage of the application, and presumably based on how well-received it is, will roll out to the remaining 50%.
The update is set for a release on the 12th of February so if you do use Firefox Focus, then perhaps this could be a feature to look forward to.