There is no real reason to use to large speaker wire, but if it's cheap I guess why not...
From BCAE site:
Resistance in Speaker Wire:
Many people are told that they need to use very large speaker wire to prevent a noticeable loss in output. For most situations, 16g speaker wire is absolutely fine. In the following calculator, you can see just how little loss you'll have with a given wire size. Keep in mind that 1 dB is generally the minimum difference you'll be able to hear. If the loss is less than 1dB, you'll never hear it.
Here is a handy Calculator (http://www.bcae1.com/images/swfs/spe...rassistant.swf
) to find all you need to know about your wire run at any length and gauge.
Assuming a 100 WPC receiver a 10ft run of 16 gauge will have a loss of 0.09db, 12 gauge lowers it to 0.03db. Since anything less than 1db is undetectable to human hearing it really doesn't give you any advantage to go thick.