Hey,
Why this is better?
Because it does not force knowledge of a specific serialization format onto the entity object and does not prevent constructing it from its composited-in parts.
Note that this is about the PHP codebase of Wikibase. It has no impact on the users of the software, such as Wikidata.org.
Cheers
-- Jeroen De Dauw - http://www.bn2vs.com Software craftsmanship advocate Evil software architect at Wikimedia Germany ~=[,,_,,]:3