Anyone have anything to say about Kelly positions?

So I tend not to talk about the 100 bazillion Kelly Scientific Research positions that tend to pop now nowadays. It's mostly because I don't find them particularly relevant to Chemjobber's readership.

But a reader writes in with a good question: "Are these legitimate job postings that I should be applying for, or should I not waste my time?  I guess I do not fully understand what these are and am curious to know what you think about them."

It seems to me that they're mostly aimed at, for example, enticing employees from other companies (i.e. experienced workers). Here's a nice example: it's a temp-to-hire position in West Lafayette in process chemistry/formulation. They'd like you to have experience in:

"Polymorphism and Salt Screening in Pharmaceutical Systems, X-ray Powder Diffraction, Differential Scanning Calorimetry, Thermogravimetric Analysis, Optical Microscopy, Crystallization Studies, Co-Crystal Screening, Crystal Form Isolation, and Crystallization Kinetic Studies. The ideal candidate would have a bachelors or masters degree in chemistry and at least one year work experience in a lab."

So an young, but experienced B.S./M.S. process chemist -- why would they want a temp position? (unless, of course, they were out of work or were coming to the end of their previous contract.)

There's also a lot of lab technician or midnight QC chemist positions available. There's nothing particularly wrong with them, but they just don't seem to be very tempting. So I'm pretty "meh" about Kelly, which is why I don't post on a lot of their jobs. Readers, you've probably had a lot more experience with them. Any thoughts?