Yes and No
It will come down to the power consumption cost versus the points you return. Only the person paying the bill can decide if that is worth it.
Modern hardware will be more powerful and thus do more work for a certain energy cost. Older hardware may not be able to access the more strenuous workunits to return them in a timely fashion and thus the returns may be small.
Although distributed computing was marketed on the basis that your computer was not being fully used so you could make use of the spare processing power, in fact using that spare cpu capacity means the pc uses more energy. If your crap PC has to be on for other things, you might think the extra juice being used is justified, you might not.
