Yes. The 'Approve' step is there to ensure orderly and coordinated activation of user accounts. You can make it more efficient by setting up a filter on the Organisations tab on admin: select 'no' in the Approved dropdown filter so as to show only the entries you've recently added. The filter remains in place as you add new companies, so you don't need to search for them in order to approve them.
For more information on manually adding attendees, have a look at this article.