I guess it has to do with historical reasons – eZP was developed in a time when private/protected did not exist in php.

In the end it is more a matter of style (or philosophy): using $obj->attribute(‘xxx’) and $obj->setattribute(‘xxx’, ‘val’) is more verbose but:
- it matches more closely the way the objects are accessed in templates (ie. every property of an object that is available in template code you can access in php code via attribute() calls)
- it matches more closely the “property” pattern that was intended in the beginning by the developers (some of those calls to attribute() will access actual object members, some will access functions, so if you access members directly it means you either have checked that they are members and not functions and that your code will break in the future if the object definition is changed – unlikely but possible)

As a side note: an interesting projects (on projects.ez.no) to help you extracting data from ezpersitsentobjects: ggxmlview.
It allows to
- map ezpo to json or xml using templates
- map ezpo to a plain php array using a single php call
(of course recursion is considered)

Excellent and useful.
Just a quick note : It’s a bad practice to access data directly from properties (Username: $user->Login). You should always use the attribute() accessor when your object is extending eZPersistentObject (Username: $user->attribute(‘login’).
See eZUser::definition() to list all attributes available with this method (see “fields” and “function_attributes”

Cheers !