That does nothing to seal the attic where can lights would be losing air. And those measures only work if done correctly, which blower door testing has shown that it’s typically not done correctly.I wouldn't worry too much about a perfect seal on can lights in the ceiling if you have 14 inches of blown in insulation over the top of them. Also most houses built in OK for the last 10 years have Zip Board exterior sheathing that is taped at every joint, crack, door, and window, and if you pay for the super caulk package that makes the house envelope pretty darn tight.