The Answers site has several advantages over the forum.
1) It is a database of searchable and tag-able ideas.Thus in theory easier to find an idea or topic.
2) You can vote on Feature Requests thus giving more control over the old thumbs up approach.
It current disadvantage is it is under a support and thus may not be seen by as many eyes.
Currently Presonus will use both sources among others as a form of customer requests.