I think it has been covered before that Facebook already has a hunch if two people seem to be interested in each other -- groups, events, messages they share, times they have visited each other profiles, and reaction counts proportional to posts after the friendship was started.

I think the fact that they also announced incognito mode today suggests that this dating feature could be passive. Like, if you browse Facebook normally and you are both using this feature, and Facebook sees you are both stalking each other rather much, it could break the ice for you. This is probably the better the more oblivious you are and I can see the value in this.

It will also be interesting to see how this feature will be rolled out. While there can be a mutual attraction between two people, I can see it being a challenge to programmatically figure out whether there exist any other reasons why the relationship could not work, e.g. logistics, and how well is Facebook able to identify such possible problems before initiating the icebreaker.