Could someone please explain this ? I don't understand what he means: "I don’t think they [Flatpaks] have the security story and I also don’t think they have

Could someone please explain this ? I don't understand what he means: "I don’t think they [Flatpaks] have the security story and I also don’t think they have the ability to deliver the same integrity of execution over time that Snaps have ‘cos we built those things into Snaps"