Larger companies often use temps. By this, she meant that temps must meld with a client's corporate culture. Entrepreneurial types do not fit in well here. Temps are typically people who have been through the wars and now just want to make a decent wage on a number of interesting projects. They may also be using temping as a strategy to check out possible regular jobs.
Companies often offer exceptional temps permanent jobs when their projects end.
However, for strategic, proprietary, or mission-critical work, hiring managers want employees, not temps. They use temps for more standard jobs and ones where confidentiality is less of an issue. I believe that this is a perception issue. Although I pointed out that the same confidentiality agreements could be used for both temps and employees, the tendency still is to use regular employees for sensitive work. Working for temp agencies has a number of benefits.