What? This is a wonderful way to use computers. Screenshots are offline storage of specific, useful information in a universal format whose content can be browsed and recognized at a glance.
People don't want better organization, they want to get their boarding pass out easily. You can do that a million ways, but the one way that makes no sense is "pull up the virtual letter I received at time of purchase and see if it contains an embedded image or an attachment I forgot to download". What would make more sense is to have an extension to something like vCard called "tickets" and allow special ticket-holding apps to keep them. Your email client could download them and pass them to the app automatically, ensuring you always have your tickets offline and organized in a dedicated ticket program.
We don't have to live in a world where one application tries to do everything, and we can use standards to make universal things (like tickets) actually universal.