A good temp agency will work with their applicants to find what they are looking for. Employment that suits their skills, and will promote a long term relationship between employers and workers, with the eventual goal of full time employment and a promising career.
Just because you are a ‘temp worker’ does not mean you are worth less than someone hired direct. You have skills, value, and worth. A poor agency will attempt to put you somewhere because they need an opening filled. Often contrary to what is best for the worker.
If you find your agency places you for work inconsistently, this should raise some red flags. Working one day a week here or two days there will not get you where you need to be. Bring up your concerns, or look elsewhere.
Your temp agency should offer you benefits such as health insurance, sick time accrual, and workman’s compensation should you be injured on the job. Often there will be a trial period before robust benefits, such as sick time, will become active.
If you need work immediately and don’t care what you must do this could be a good fit for you. If you are looking for work that will accentuate your skills you do not have to accept the first position offered. That could just be setting yourself up for failure.