I worked for a temp agency. I started off calling every day to see if there was a job, no guarantee, and it was light manual labor like banquet staff. Once I established a good record for showing up, like a month, they started temp to hire positions. However in my case temp to hire never resulted in permanent employment but I also left with four letters of reference because the lack of hire in three jobs was due to someone high up deciding they needed a different position created instead of bringing on an accounting/administrative clerk and the fourth was long term temp, not temp to hire. I did have a manager from one of the light labor jobs I was at a few weeks call me after the 3 months no-hire period wanting to hire me directly, but I had already found another job elsewhere.
It did bolster the resume though. Because of the several long-term assignments I had a solid two year job history instead of bouncing around. Most of that was accounting/administrative, which is nice for directly landing a cushy office job. And I had specialty experience in several fields which opens the door to a lot of "experience required/experience preferred" jobs. I actually used that to get a job that I had no experience in, because I used it to say I could pick up new information/skills really, really fast.