Maybe I'm still not being clear. I don't think people mean "the effects of having slept" in a symptomatic sense, either (alertness, etc.)

Rather, what people want is "the effects of having slept" in a physiological sense: a pill that rapidly sweeps the same toxins out of your body that sleep does gradually. Taking such a pill would have all the same long-term benefits that a healthy sleep schedule would have.

Of course, a "pill" that did this properly would likely have to contain something like complex organic-waste-molecule-chellating molecules, or perhaps even biofilm-scrubbing nanomachines. :)