TYPO3 Core

What are you exactly missing you can not access through getProperties()?

You're rigth. It is possible to get "crop" from getProperties. It was just more intuitive to get it directly but I have to say that we can stay with that.

There are only a few fields directly accessible through getter methods. The rest of the sys_file_reference record you can access through the getProperties() method.

Think that's enough as you can easily add more properties to your sys_file_reference and there are also not accessible through direct getter methods but are through getProperties().