Except that planes have (supposedly) trained staff that can go around and make sure everyone is getting oxygen. These pods are automated and would most likely have no staff on board.

Putting on an oxygen mask is not a difficult operation.

Unless you are otherwise incapacitated due to whatever is causing the emergency in the first place.

You can always push "emergency break, quickly depresurize tube and open doors" button. No such luck in plane, and planes are still safer than cars.