Staffing agencies, aka recruitment consultancies, aka employment services are not there to help the candidate. They will waste your time, steal your information and sell it to the companies for money.
If you do get hired through an agency, they take a cut of your wage. They don't do anything but pass around balk resumes. They are leeches.
They are also very sneaky, and will post a general looking job descriptions with low requirements. Once you submit your info, you'll most likely never hear back. It just wastes your time and energy.