Well, the gallery is indeed a complete object, and has the description method. It is just that there is no database table associated with the gallery object.
All Zenphoto objects contain the method `$obj->getDesc()` which will return the description in the current language (assuming the site is multi-lingual). [Well, maybe not all, but all for which a description makes sense.]
The `$obj->get(item)` method should almost never be used. It directly fetches the database table element for the [i]item[/i] column. This bypasses any method algorithms (like selecting the current language from the description element.)