I worked as a 'temp' for Manpower many years ago and after a certain period of time you were entitled to holiday pay, we also got some free training (eg wordprocessing) in the office when we weren't allocated any work.
Working as a 'temp' at that period in time was perfect for me as I moved to a different area and could earn money each week whilst still looking for a permanent job, so even though I wasn't earning as much as I could have been had I been in a permanent job I was probably exploiting them as much as they were exploiting me.