The CDC has said that COVID doesn't transmit easily on objects. Case in point: we believe no one has become infected by eating food prepared in a restaurant or food packages picked up at a grocery store -- and as long as we've been dealing with this, someone with the virus has touched someone's food packaging. The virus' spread is airborne.
A stick has several small benefits over a hand: being smaller, less surface area. And a stick is room temperature and doesn't sweat -- so it eliminates the warm, damp climate that viruses favor. These are small issues; if you're willing to go to Disney, this probably won't be a deciding factor.
But, in truth, we've been using it for school events because 1) it feels less invasive to the owner of the bag and 2) it eliminates the possibility of a needle stick (or similar) for the checker.
Interesting -- is this like the airport? I'm thinking it would speed up bag checks, which everyone would welcome.