A parliamentarian is an expert on running meetings.  Organizations hire professional parliamentarians to ensure that procedural rules are observed–not to preserve some arbitrary and wooden form, but rather to ensure that each member is treated fairly and that meetings run smoothly.

In some situations, a professional parliamentarian may be able to cut hours or even days from the regular length of a membership/board meeting or convention.  Furthermore, a professional parliamentarian is trained to help an organization avoid the kind of procedural violations that could end up in costly litigation.