Cheaper than coffee, doesn't spill, and no need to be heading to the bathroom every 15 minutes.
Employers probably don't provide the pills for free though because it's easier to OD yourself to death on the things.
Just think of the savings though...

reduction in time spent in bathrooms, reduction in time spent walking to and from the coffee machine, slight reduction in worker animosity resulting from dickweeds who leave the pot empty, and no need for coffee supply delivery service or a commercial-grade machine. I may be slightly biased, as I find the taste of plain coffee to be awful.