Also related is David Schwartz' answer to this similar question "Is there a way to set up proof-of-work systems so it would be even more useful?"
David responds, "The work is not useless, it secures the transactions. The public hash chain ensures that Bitcoins can only be spent once... There is currently no known way to make the work more useful. " See http://bitcoin.stackexchange.com/a/334
David responds, "The work is not useless, it secures the transactions. The public hash chain ensures that Bitcoins can only be spent once... There is currently no known way to make the work more useful. " See http://bitcoin.stackexchange.com/a/334