One of the things that is confusing about Drupal is the use of the word node.
In my opinion “node” is just the wrong word.
When you read node think content.
Content (in the context of a website) means something that is displayed to users.
Content can be text, images, video, even flash games.
So when you create a node in Drupal you are creating content.
Sometimes Drupal actually uses the word content. The admin interface allows you to create “content types”, “create content” takes you to the url node/add, and through “content management” you get to a list of nodes.
This linguistic confusion can lead people to use nodes where they don’t really fit. Nodes aren’t so suitable for data storage - if you have a lot of data that isn’t displayed to the user - then it isn’t content so don’t make it into a node.
Data belongs in well designed database tables.
I’d like to see node renamed to “content” but in the meantime I recommend translating node to content mentally.