the pull tab on the right has a divot in it where it makes contact with the can, and it concentrates more pressure at the point of contact to pop the seal.

That’s an attempt to mitigate cans where you’d pull the tab and the tab would just break off without opening the can. So the person who answered it’s usually because of the seal is right.

other half’s dad [retired from] Campbell in Ohio and isn’t an internet let alone a Reddit person, you’d never guess how much trivia there is about their #2 can. I’d have commented but a brand new account will probably be buried as spam … and the second answer is correct anyway.